diff --git a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/service/DeviceManagementProviderServiceImpl.java b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/service/DeviceManagementProviderServiceImpl.java
index 5428950483..1b75f2dd4b 100644
--- a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/service/DeviceManagementProviderServiceImpl.java
+++ b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/service/DeviceManagementProviderServiceImpl.java
@@ -160,15 +160,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public boolean enrollDevice(Device device) throws DeviceManagementException {
-        if (device != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Enrolling the device " + device.getId() + "of type '" + device.getType() + "'");
-            }
-        } else {
-            String msg = "required values are not set for device enrollment";
+        if (device == null) {
+            String msg = "Received empty device for device enrollment";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Enrolling the device " + device.getId() + "of type '" + device.getType() + "'");
+        }
         boolean status = false;
         DeviceIdentifier deviceIdentifier = new DeviceIdentifier(device.getDeviceIdentifier(), device.getType());
 
@@ -237,15 +236,15 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
                         }
                     } catch (DeviceManagementDAOException e) {
                         DeviceManagementDAOFactory.rollbackTransaction();
-                        String msg = "Error occurred while adding enrolment related metadata";
+                        String msg = "Error occurred while adding enrolment related metadata for device: " + device.getId();
                         log.error(msg, e);
                         throw new DeviceManagementException(msg, e);
                     } catch (TransactionManagementException e) {
-                        String msg = "Error occurred while initiating transaction";
+                        String msg = "Error occurred while initiating transaction to enrol device: " + device.getId();
                         log.error(msg);
                         throw new DeviceManagementException(msg, e);
                     } catch (Exception e) {
-                        String msg = "Error occurred";
+                        String msg = "Error occurred while enrolling device: " + device.getId();
                         log.error(msg, e);
                         throw new DeviceManagementException(msg, e);
                     } finally {
@@ -272,7 +271,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
                 log.error(msg, e);
                 throw new DeviceManagementException(msg, e);
             } catch (Exception e) {
-                String msg = "Error occurred";
+                String msg = "Error occurred while enrolling device: " + device.getId();
                 log.error(msg, e);
                 throw new DeviceManagementException(msg, e);
             } finally {
@@ -298,16 +297,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public boolean modifyEnrollment(Device device) throws DeviceManagementException {
-        if (device != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Modifying enrollment for device: " + device.getId() + " of type '" + device.getType() + "'");
-            }
-        } else {
-            String msg = "required values are not set to modify device enrollment";
+        if (device == null) {
+            String msg = "Required values are not set to modify device enrollment";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
-
+        if (log.isDebugEnabled()) {
+            log.debug("Modifying enrollment for device: " + device.getId() + " of type '" + device.getType() + "'");
+        }
         DeviceManager deviceManager = this.getDeviceManager(device.getType());
         DeviceIdentifier deviceIdentifier = new DeviceIdentifier(device.getDeviceIdentifier(), device.getType());
         if (deviceManager == null) {
@@ -339,11 +336,11 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg);
             throw new DeviceManagementException(msg, e);
         } catch (TransactionManagementException e) {
-            String msg = "Error occurred while initiating transaction";
+            String msg = "Error occurred while initiating transaction to modify device: " + device.getId();
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred while modifying device: " + device.getId();
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -354,6 +351,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     private List<EnrolmentInfo> getEnrollmentsOfUser(int deviceId, String user)
             throws DeviceManagementException {
+        if (user == null || user.isEmpty()) {
+            String msg = "Required values are not set to getEnrollmentsOfUser";
+            log.error(msg);
+            throw new DeviceManagementException(msg);
+        }
+        if (log.isDebugEnabled()) {
+            log.debug("Get enrollments for user '" + user + "' device: " + deviceId);
+        }
         List<EnrolmentInfo> enrolmentInfos = new ArrayList<>();
         try {
             DeviceManagementDAOFactory.openConnection();
@@ -368,7 +373,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getEnrollmentsOfUser user '" + user + "' device: " + deviceId;
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -379,15 +384,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public boolean disenrollDevice(DeviceIdentifier deviceId) throws DeviceManagementException {
-        if (deviceId != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Dis-enrolling device: " + deviceId.getId() + " of type '" + deviceId.getType() + "'");
-            }
-        } else {
-            String msg = "required values are not set to dis-enroll device";
+        if (deviceId == null) {
+            String msg = "Required values are not set to dis-enroll device";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Dis-enrolling device: " + deviceId.getId() + " of type '" + deviceId.getType() + "'");
+        }
         DeviceManager deviceManager = this.getDeviceManager(deviceId.getType());
         if (deviceManager == null) {
             if (log.isDebugEnabled()) {
@@ -409,7 +413,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
         if (device.getEnrolmentInfo().getStatus().equals(EnrolmentInfo.Status.REMOVED)) {
             if (log.isDebugEnabled()) {
-                log.debug("Device has already disenrolled : " + deviceId.getId() + "'");
+                log.debug("Device has already dis-enrolled : " + deviceId.getId() + "'");
             }
             return true;
         }
@@ -433,7 +437,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred while dis-enrolling device: " + deviceId.getId();
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -484,15 +488,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public List<Device> getAllDevices(String deviceType, boolean requireDeviceInfo) throws DeviceManagementException {
-        if (deviceType != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Getting all devices of type '" + deviceType + "' and requiredDeviceInfo: " + requireDeviceInfo);
-            }
-        } else {
+        if (deviceType == null) {
             String msg = "Device type is empty for method getAllDevices";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Getting all devices of type '" + deviceType + "' and requiredDeviceInfo: " + requireDeviceInfo);
+        }
         List<Device> allDevices;
         try {
             DeviceManagementDAOFactory.openConnection();
@@ -513,7 +516,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred while getting all devices of device type '" + deviceType + "'";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -548,7 +551,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in get all devices";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -568,16 +571,15 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public List<Device> getDevices(Date since, boolean requireDeviceInfo) throws DeviceManagementException {
-        if (since != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Getting all devices since date '" + since.toString() + "' and required device info: "
-                        + requireDeviceInfo);
-            }
-        } else {
+        if (since == null) {
             String msg = "Given date is empty for method getDevices";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Getting all devices since date '" + since.toString() + "' and required device info: "
+                    + requireDeviceInfo);
+        }
         List<Device> allDevices;
         try {
             DeviceManagementDAOFactory.openConnection();
@@ -591,7 +593,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred get devices since '" + since.toString() + "'";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -611,15 +613,15 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public PaginationResult getDevicesByType(PaginationRequest request, boolean requireDeviceInfo) throws DeviceManagementException {
-        if (request != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get devices with pagination " + request.toString() + " and required deviceinfo: " + requireDeviceInfo);
-            }
-        } else {
-            String msg = "received incomplete pagination request for getDevicesByType";
+        if (request == null) {
+            String msg = "Received incomplete pagination request for getDevicesByType";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get devices with pagination " + request.toString() + " and required deviceinfo: "
+                    + requireDeviceInfo);
+        }
         PaginationResult paginationResult = new PaginationResult();
         List<Device> allDevices = new ArrayList<>();
         int count = 0;
@@ -640,7 +642,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDeviceByType";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -665,15 +667,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public PaginationResult getAllDevices(PaginationRequest request, boolean requireDeviceInfo) throws DeviceManagementException {
-        if (request != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get devices with pagination " + request.toString() + " and requiredDeviceInfo: " + requireDeviceInfo);
-            }
-        } else {
-            String msg = "received incomplete pagination request for method getAllDevices";
+        if (request == null) {
+            String msg = "Received incomplete pagination request for method getAllDevices";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get devices with pagination " + request.toString() + " and requiredDeviceInfo: " + requireDeviceInfo);
+        }
         List<Device> devicesForRoles = null;
         PaginationResult paginationResult = new PaginationResult();
         List<Device> allDevices = new ArrayList<>();
@@ -702,7 +703,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
                 log.error(msg, e);
                 throw new DeviceManagementException(msg, e);
             } catch (Exception e) {
-                String msg = "Error occurred";
+                String msg = "Error occurred in getAllDevices";
                 log.error(msg, e);
                 throw new DeviceManagementException(msg, e);
             } finally {
@@ -721,16 +722,15 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public Device getDevice(DeviceIdentifier deviceId, boolean requireDeviceInfo) throws DeviceManagementException {
-        if (deviceId != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get device by device id :" + deviceId.getId() + " of type '" + deviceId.getType()
-                        + "' and requiredDeviceInfo: " + requireDeviceInfo);
-            }
-        } else {
-            String msg = "received null device identifier for method getDevice";
+        if (deviceId == null) {
+            String msg = "Received null device identifier for method getDevice";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get device by device id :" + deviceId.getId() + " of type '" + deviceId.getType()
+                    + "' and requiredDeviceInfo: " + requireDeviceInfo);
+        }
         int tenantId = this.getTenantId();
         Device device = this.getDeviceFromCache(deviceId);
         if (device == null) {
@@ -755,7 +755,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
                 log.error(msg);
                 throw new DeviceManagementException(msg, e);
             } catch (Exception e) {
-                String msg = "Error occurred";
+                String msg = "Error occurred in getDevice: " + deviceId.getId();
                 log.error(msg, e);
                 throw new DeviceManagementException(msg, e);
             } finally {
@@ -770,15 +770,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public void sendEnrolmentInvitation(String templateName, EmailMetaInfo metaInfo) throws DeviceManagementException {
-        if (metaInfo != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Send enrollment invitation, templateName '" + templateName + "'");
-            }
-        } else {
-            String msg = "received incomplete data to method sendEnrolmentInvitation";
+        if (metaInfo == null) {
+            String msg = "Received incomplete data to method sendEnrolmentInvitation";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Send enrollment invitation, templateName '" + templateName + "'");
+        }
         Map<String, TypedValue<Class<?>, Object>> params = new HashMap<>();
         Properties props = metaInfo.getProperties();
         Enumeration e = props.propertyNames();
@@ -800,7 +799,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, ex);
             throw new DeviceManagementException(msg, ex);
         } catch (Exception ex) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in setEnrollmentInvitation";
             log.error(msg, ex);
             throw new DeviceManagementException(msg, ex);
         }
@@ -808,15 +807,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public void sendRegistrationEmail(EmailMetaInfo metaInfo) throws DeviceManagementException {
-        if (metaInfo != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Send registration email");
-            }
-        } else {
-            String msg = "received incomplete request for sendRegistrationEmail";
+        if (metaInfo == null) {
+            String msg = "Received incomplete request for sendRegistrationEmail";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Send registration email");
+        }
         Map<String, TypedValue<Class<?>, Object>> params = new HashMap<>();
         params.put(org.wso2.carbon.device.mgt.core.DeviceManagementConstants.EmailAttributes.FIRST_NAME,
                 new TypedValue<Class<?>, Object>(String.class, metaInfo.getProperty("first-name")));
@@ -843,7 +841,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in sendRegistrationEmail";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         }
@@ -851,16 +849,15 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public HashMap<Integer, Device> getTenantedDevice(DeviceIdentifier deviceIdentifier) throws DeviceManagementException {
-        if (deviceIdentifier != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get tenanted device with id: " + deviceIdentifier.getId() + " of type '" +
-                        deviceIdentifier.getType() + "'");
-            }
-        } else {
-            String msg = "received null deviceIdentifier for getTenantedDevice";
+        if (deviceIdentifier == null) {
+            String msg = "Received null deviceIdentifier for getTenantedDevice";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get tenanted device with id: " + deviceIdentifier.getId() + " of type '" +
+                    deviceIdentifier.getType() + "'");
+        }
         HashMap<Integer, Device> deviceHashMap;
         try {
             DeviceManagementDAOFactory.openConnection();
@@ -881,7 +878,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getTenantedDevice device: " + deviceIdentifier.getId();
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -897,15 +894,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public Device getDeviceWithTypeProperties(DeviceIdentifier deviceId) throws DeviceManagementException {
-        if (deviceId != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get tenanted device with type properties, deviceId: " + deviceId.getId());
-            }
-        } else {
-            String msg = "received null deviceIdentifier for getDeviceWithTypeProperties";
+        if (deviceId == null) {
+            String msg = "Received null deviceIdentifier for getDeviceWithTypeProperties";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get tenanted device with type properties, deviceId: " + deviceId.getId());
+        }
         Device device = this.getDevice(deviceId, false);
 
         DeviceManager deviceManager = this.getDeviceManager(device.getType());
@@ -932,16 +928,15 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public Device getDevice(DeviceIdentifier deviceId, Date since, boolean requireDeviceInfo) throws DeviceManagementException {
-        if (deviceId != null && since != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get device since '" + since.toString() + "' with identifier: " + deviceId.getId()
-                        + " and type '" + deviceId.getType() + "'");
-            }
-        } else {
-            String msg = "received incomplete data for getDevice";
+        if (deviceId == null || since == null) {
+            String msg = "Received incomplete data for getDevice";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get device since '" + since.toString() + "' with identifier: " + deviceId.getId()
+                    + " and type '" + deviceId.getType() + "'");
+        }
         Device device;
         try {
             DeviceManagementDAOFactory.openConnection();
@@ -962,7 +957,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDevice for device: " + deviceId.getId();
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -982,15 +977,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     @Override
     public Device getDevice(DeviceIdentifier deviceId, EnrolmentInfo.Status status, boolean requireDeviceInfo)
             throws DeviceManagementException {
-        if (deviceId != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get device with identifier: " + deviceId.getId() + " and type '" + deviceId.getType() + "'");
-            }
-        } else {
-            String msg = "received null deviceIdentifier for getDevice";
+        if (deviceId == null) {
+            String msg = "Received null deviceIdentifier for getDevice";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get device with identifier: " + deviceId.getId() + " and type '" + deviceId.getType() + "'");
+        }
         Device device;
         try {
             DeviceManagementDAOFactory.openConnection();
@@ -1011,7 +1005,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDevice for device: " + deviceId.getId();
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1071,7 +1065,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.info(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getAvailableDeviceTypes";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1082,15 +1076,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public boolean updateDeviceInfo(DeviceIdentifier deviceId, Device device) throws DeviceManagementException {
-        if (deviceId != null && device != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Update device info of device: " + deviceId.getId());
-            }
-        } else {
-            String msg = "received incomplete data for updateDeviceInfo";
+        if (deviceId == null || device == null) {
+            String msg = "Received incomplete data for updateDeviceInfo";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Update device info of device: " + deviceId.getId());
+        }
         DeviceManager deviceManager = this.getDeviceManager(deviceId.getType());
         if (deviceManager == null) {
             if (log.isDebugEnabled()) {
@@ -1104,15 +1097,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public boolean setOwnership(DeviceIdentifier deviceId, String ownershipType) throws DeviceManagementException {
-        if (deviceId != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Set ownership of device: " + deviceId.getId() + " ownership type '" + ownershipType + "'");
-            }
-        } else {
-            String msg = "received incomplete data for setOwnership";
+        if (deviceId == null) {
+            String msg = "Received incomplete data for setOwnership";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Set ownership of device: " + deviceId.getId() + " ownership type '" + ownershipType + "'");
+        }
         DeviceManager deviceManager = this.getDeviceManager(deviceId.getType());
         if (deviceManager == null) {
             if (log.isDebugEnabled()) {
@@ -1140,15 +1132,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     @Override
     public boolean setStatus(DeviceIdentifier deviceId, String currentOwner,
                              EnrolmentInfo.Status status) throws DeviceManagementException {
-        if (deviceId != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Set status of device: " + deviceId.getId());
-            }
-        } else {
-            String msg = "received null deviceIdentifier for setStatus";
+        if (deviceId == null) {
+            String msg = "Received null deviceIdentifier for setStatus";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Set status of device: " + deviceId.getId());
+        }
         try {
             boolean success = false;
             int tenantId = this.getTenantId();
@@ -1171,7 +1162,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in setStatus for device :" + deviceId.getId();
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1202,7 +1193,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in setStatus";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1226,15 +1217,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public License getLicense(String deviceType, String languageCode) throws DeviceManagementException {
-        if (deviceType != null && languageCode != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get the licence for device type '" + deviceType + "' languageCode '" + languageCode + "'");
-            }
-        } else {
-            String msg = "received incomplete data for getLicence";
+        if (deviceType == null || languageCode == null) {
+            String msg = "Received incomplete data for getLicence";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get the licence for device type '" + deviceType + "' languageCode '" + languageCode + "'");
+        }
         DeviceManager deviceManager = this.getDeviceManager(deviceType);
         License license;
         if (deviceManager == null) {
@@ -1258,7 +1248,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getLicence for device type '" + deviceType + "'";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         }
@@ -1266,15 +1256,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public void addLicense(String deviceType, License license) throws DeviceManagementException {
-        if (deviceType != null && license != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Add the licence for device type '" + deviceType + "'");
-            }
-        } else {
-            String msg = "received incomplete data for addLicence";
+        if (deviceType == null || license == null) {
+            String msg = "Received incomplete data for addLicence";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Add the licence for device type '" + deviceType + "'");
+        }
         DeviceManager deviceManager = this.getDeviceManager(deviceType);
         if (deviceManager == null) {
             if (log.isDebugEnabled()) {
@@ -1290,7 +1279,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in addLicence for device type '" + deviceType + "'";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         }
@@ -1425,7 +1414,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     @Override
     public List<Device> getDevicesOfUser(String username, boolean requireDeviceInfo) throws DeviceManagementException {
         if (username == null) {
-            String msg = "username null in getDevicesOfUser";
+            String msg = "Username null in getDevicesOfUser";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
@@ -1446,7 +1435,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDevicesOfUser for username '" + username + "'";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1467,16 +1456,15 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     @Override
     public List<Device> getDevicesOfUser(String username, String deviceType, boolean requireDeviceInfo) throws
             DeviceManagementException {
-        if (username != null && deviceType != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get '" + deviceType + "' devices of user with username '" + username + "' requiredDeviceInfo: "
-                        + requireDeviceInfo);
-            }
-        } else {
-            String msg = "received incomplete data for getDevicesOfUser";
+        if (username == null || deviceType == null) {
+            String msg = "Received incomplete data for getDevicesOfUser";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get '" + deviceType + "' devices of user with username '" + username + "' requiredDeviceInfo: "
+                    + requireDeviceInfo);
+        }
         List<Device> userDevices;
         try {
             DeviceManagementDAOFactory.openConnection();
@@ -1491,7 +1479,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDevicesOfUser for '" + username + "'";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1512,16 +1500,15 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     @Override
     public PaginationResult getDevicesOfUser(PaginationRequest request, boolean requireDeviceInfo)
             throws DeviceManagementException {
-        if (request != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get paginated results of devices of user " + request.toString() + " and requiredDeviceInfo: "
-                        + requireDeviceInfo);
-            }
-        } else {
-            String msg = "received incomplete pagination request for getDevicesOfUser";
+        if (request == null) {
+            String msg = "Received incomplete pagination request for getDevicesOfUser";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get paginated results of devices of user " + request.toString() + " and requiredDeviceInfo: "
+                    + requireDeviceInfo);
+        }
         PaginationResult result = new PaginationResult();
         int deviceCount = 0;
         int tenantId = this.getTenantId();
@@ -1541,7 +1528,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDevicesOfUser";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1568,15 +1555,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     @Override
     public PaginationResult getDevicesByOwnership(PaginationRequest request, boolean requireDeviceInfo)
             throws DeviceManagementException {
-        if (request != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get devices by ownership " + request.toString());
-            }
-        } else {
-            String msg = "received incomplete data for getDevicesByOwnership";
+        if (request == null) {
+            String msg = "Received incomplete data for getDevicesByOwnership";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get devices by ownership " + request.toString());
+        }
         PaginationResult result = new PaginationResult();
         List<Device> allDevices;
         int deviceCount = 0;
@@ -1596,7 +1582,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDevicesByOwnership";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1620,15 +1606,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public List<Device> getAllDevicesOfRole(String role, boolean requireDeviceInfo) throws DeviceManagementException {
-        if (role != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get devices of role '" + role + "' and requiredDeviceInfo: " + requireDeviceInfo);
-            }
-        } else {
-            String msg = "received empty role for the method getAllDevicesOfRole";
+        if (role == null || role.isEmpty()) {
+            String msg = "Received empty role for the method getAllDevicesOfRole";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get devices of role '" + role + "' and requiredDeviceInfo: " + requireDeviceInfo);
+        }
         List<Device> devices = new ArrayList<>();
         String[] users;
         int tenantId = this.getTenantId();
@@ -1640,7 +1625,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getAllDevicesOfRole for role '" + role + "'";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         }
@@ -1656,7 +1641,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
                 log.error(msg, e);
                 throw new DeviceManagementException(msg, e);
             } catch (Exception e) {
-                String msg = "Error occurred";
+                String msg = "Error occurred getAllDevicesOfRole for role '" + role + "'";
                 log.error(msg, e);
                 throw new DeviceManagementException(msg, e);
             } finally {
@@ -1671,15 +1656,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
 
     @Override
     public int getDeviceCount(String username) throws DeviceManagementException {
-        if (username != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Getting device count of the user '" + username + "'");
-            }
-        } else {
-            String msg = "received empty username for getDeviceCount";
+        if (username == null) {
+            String msg = "Received empty username for getDeviceCount";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Getting device count of the user '" + username + "'");
+        }
         try {
             DeviceManagementDAOFactory.openConnection();
             return deviceDAO.getDeviceCount(username, this.getTenantId());
@@ -1692,7 +1676,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDeviceCount for username '" + username + "'";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1717,7 +1701,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDeviceCount";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1728,15 +1712,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     @Override
     public List<Device> getDevicesByNameAndType(PaginationRequest request, boolean requireDeviceInfo)
             throws DeviceManagementException {
-        if (request != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get devices by name " + request.toString() + " and requiredDeviceInfo: " + requireDeviceInfo);
-            }
-        } else {
-            String msg = "received incomplete data for getDevicesByNameAndType";
+        if (request == null) {
+            String msg = "Received incomplete data for getDevicesByNameAndType";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get devices by name " + request.toString() + " and requiredDeviceInfo: " + requireDeviceInfo);
+        }
         List<Device> devices = new ArrayList<>();
         List<Device> allDevices;
         int limit = DeviceManagerUtil.validateDeviceListPageSize(request.getRowCount());
@@ -1756,7 +1739,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDevicesByNameAndType";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1777,15 +1760,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     @Override
     public PaginationResult getDevicesByName(PaginationRequest request, boolean requireDeviceInfo) throws
             DeviceManagementException {
-        if (request != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get devices by name " + request.toString() + " requiredDeviceInfo: " + requireDeviceInfo);
-            }
-        } else {
-            String msg = "received incomplete data for getDevicesByName";
+        if (request == null) {
+            String msg = "Received incomplete data for getDevicesByName";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get devices by name " + request.toString() + " requiredDeviceInfo: " + requireDeviceInfo);
+        }
         PaginationResult result = new PaginationResult();
         int tenantId = this.getTenantId();
         List<Device> allDevices = new ArrayList<>();
@@ -1806,7 +1788,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDevicesByName";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1823,15 +1805,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     @Override
     public void updateDeviceEnrolmentInfo(Device device, EnrolmentInfo.Status status) throws DeviceManagementException {
         try {
-            if (device != null && status != null) {
-                if (log.isDebugEnabled()) {
-                    log.debug("Updating enrolment for device: " + device.getId() + " of type '" + device.getType() + "'");
-                }
-            } else {
-                String msg = "received incomplete data for updateDeviceEnrolmentInfo";
+            if (device == null || status == null) {
+                String msg = "Received incomplete data for updateDeviceEnrolmentInfo";
                 log.error(msg);
                 throw new DeviceManagementException(msg);
             }
+            if (log.isDebugEnabled()) {
+                log.debug("Updating enrolment for device: " + device.getId() + " of type '" + device.getType() + "'");
+            }
             DeviceManagementDAOFactory.beginTransaction();
             device.getEnrolmentInfo().setDateOfLastUpdate(new Date().getTime());
             device.getEnrolmentInfo().setStatus(status);
@@ -1848,7 +1829,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in updateDeviceEnrolmentInfo";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1868,7 +1849,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
                     deviceManagementService.getType() + "'";
             log.error(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in registerDeviceManagementService";
             log.error(msg, e);
         }
     }
@@ -1884,7 +1865,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error("Error occurred while un-registering device management plugin '" +
                     deviceManagementService.getType() + "'", e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in unregisterDeviceManagementService";
             log.error(msg, e);
         }
     }
@@ -1912,7 +1893,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDevicesByStatus";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -1932,16 +1913,15 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     @Override
     public PaginationResult getDevicesByStatus(PaginationRequest request, boolean requireDeviceInfo)
             throws DeviceManagementException {
-        if (request != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("get devices by status " + request.toString() + " and requiredDeviceInfo: "
-                        + requireDeviceInfo);
-            }
-        } else {
-            String msg = "received incomplete data for getDevicesByStatus";
+        if (request == null) {
+            String msg = "Received incomplete data for getDevicesByStatus";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get devices by status " + request.toString() + " and requiredDeviceInfo: "
+                    + requireDeviceInfo);
+        }
         PaginationResult result = new PaginationResult();
         List<Device> allDevices;
         int tenantId = this.getTenantId();
@@ -1962,7 +1942,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDevicesByStatus";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -2007,16 +1987,15 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     @Override
     public boolean changeDeviceStatus(DeviceIdentifier deviceIdentifier, EnrolmentInfo.Status newStatus)
             throws DeviceManagementException {
-        if (deviceIdentifier != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Change device status of device: " + deviceIdentifier.getId() + " of type '"
-                        + deviceIdentifier.getType() + "'");
-            }
-        } else {
-            String msg = "received incomplete data for getDevicesByStatus";
+        if (deviceIdentifier == null) {
+            String msg = "Received incomplete data for getDevicesByStatus";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Change device status of device: " + deviceIdentifier.getId() + " of type '"
+                    + deviceIdentifier.getType() + "'");
+        }
         boolean isDeviceUpdated = false;
         Device device = getDevice(deviceIdentifier, false);
         int deviceId = device.getId();
@@ -2056,7 +2035,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDeviceEnrolledTenants";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -2089,7 +2068,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in updateEnrollment for deviceId: " + deviceId;
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -2130,15 +2109,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
      */
     private void addDeviceToGroups(DeviceIdentifier deviceIdentifier, EnrolmentInfo.OwnerShip ownership)
             throws DeviceManagementException {
-        if (deviceIdentifier != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Add device:" + deviceIdentifier.getId() + " to default group");
-            }
-        } else {
-            String msg = "received incomplete data for addDeviceToGroup";
+        if (deviceIdentifier == null) {
+            String msg = "Received incomplete data for addDeviceToGroup";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Add device:" + deviceIdentifier.getId() + " to default group");
+        }
         GroupManagementProviderService groupManagementProviderService = new GroupManagementProviderServiceImpl();
         try {
             DeviceGroup defaultGroup = createDefaultGroup(groupManagementProviderService, ownership.toString());
@@ -2163,16 +2141,15 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     }
 
     private void addInitialOperations(DeviceIdentifier deviceIdentifier, String deviceType) throws DeviceManagementException {
-        if (deviceIdentifier != null && deviceType != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Add initial operations to the device:" + deviceIdentifier.getId() + " of type '"
-                        + deviceType + "'");
-            }
-        } else {
-            String msg = "received incomplete data for getDevicesByStatus";
+        if (deviceIdentifier == null || deviceType == null) {
+            String msg = "Received incomplete data for getDevicesByStatus";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Add initial operations to the device:" + deviceIdentifier.getId() + " of type '"
+                    + deviceType + "'");
+        }
         DeviceManagementProviderService deviceManagementProviderService = DeviceManagementDataHolder.getInstance().
                 getDeviceManagementProvider();
         DeviceManagementService deviceManagementService =
@@ -2218,15 +2195,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
      */
     private DeviceGroup createDefaultGroup(GroupManagementProviderService service, String groupName)
             throws GroupManagementException {
-        if (service != null && groupName != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Create default group with name '" + groupName + "'");
-            }
-        } else {
-            String msg = "received incomplete data for createDefaultGroup";
+        if (service == null || groupName == null) {
+            String msg = "Received incomplete data for createDefaultGroup";
             log.error(msg);
             throw new GroupManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Create default group with name '" + groupName + "'");
+        }
         DeviceGroup defaultGroup = service.getGroup(groupName);
         if (defaultGroup == null) {
             defaultGroup = new DeviceGroup(groupName);
@@ -2262,10 +2238,10 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
     public DeviceType getDeviceType(String deviceType) throws DeviceManagementException {
         if (deviceType != null) {
             if (log.isDebugEnabled()) {
-                log.debug("get device type '" + deviceType + "'");
+                log.debug("Get device type '" + deviceType + "'");
             }
         } else {
-            String msg = "received null deviceType for getDeviceType";
+            String msg = "Received null deviceType for getDeviceType";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
@@ -2308,7 +2284,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDeviceTypes";
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } finally {
@@ -2344,15 +2320,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
      * Returns all the device-info including location of the given device.
      */
     private DeviceInfo getDeviceInfo(Device device) throws DeviceManagementException {
-        if (device != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get device info of device: " + device.getId() + " of type '" + device.getType() + "'");
-            }
-        } else {
-            String msg = "received incomplete data for getDeviceInfo";
+        if (device == null) {
+            String msg = "Received incomplete data for getDeviceInfo";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get device info of device: " + device.getId() + " of type '" + device.getType() + "'");
+        }
         DeviceInfo info = null;
         try {
             DeviceManagementDAOFactory.openConnection();
@@ -2371,7 +2346,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
             log.error(msg, e);
             throw new DeviceManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDeviceInfo for device: " + device.getId();
             log.error(msg, e);
         } finally {
             DeviceManagementDAOFactory.closeConnection();
@@ -2397,7 +2372,7 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
         } catch (SQLException e) {
             log.error("Error occurred while opening a connection to the data source", e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getInstalledApplications";
             log.error(msg, e);
         } finally {
             DeviceManagementDAOFactory.closeConnection();
@@ -2410,15 +2385,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
      * of the given device list.
      */
     private List<Device> getAllDeviceInfo(List<Device> allDevices) throws DeviceManagementException {
-        if (allDevices.size() > 0) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get all device info of devices, num of devices: " + allDevices.size());
-            }
-        } else {
-            String msg = "received empty device list for getAllDeviceInfo";
+        if (allDevices.size() == 0) {
+            String msg = "Received empty device list for getAllDeviceInfo";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get all device info of devices, num of devices: " + allDevices.size());
+        }
         List<Device> devices = new ArrayList<>();
         if (allDevices != null) {
             for (Device device : allDevices) {
@@ -2450,15 +2424,14 @@ public class DeviceManagementProviderServiceImpl implements DeviceManagementProv
      * of a given device.
      */
     private Device getAllDeviceInfo(Device device) throws DeviceManagementException {
-        if (device != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get all device info of device: " + device.getId() + " of type '" + device.getType() + "'");
-            }
-        } else {
-            String msg = "received empty device for getAllDeviceInfo";
+        if (device == null) {
+            String msg = "Received empty device for getAllDeviceInfo";
             log.error(msg);
             throw new DeviceManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get all device info of device: " + device.getId() + " of type '" + device.getType() + "'");
+        }
         device.setDeviceInfo(this.getDeviceInfo(device));
         device.setApplications(this.getInstalledApplications(device));
 
diff --git a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/service/GroupManagementProviderServiceImpl.java b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/service/GroupManagementProviderServiceImpl.java
index 592d8a4f65..b5a2a4f635 100644
--- a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/service/GroupManagementProviderServiceImpl.java
+++ b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/service/GroupManagementProviderServiceImpl.java
@@ -65,15 +65,14 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
     @Override
     public void createGroup(DeviceGroup deviceGroup, String defaultRole, String[] defaultPermissions)
             throws GroupManagementException, GroupAlreadyExistException {
-        if (deviceGroup != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Creating group '" + deviceGroup.getName() + "'");
-            }
-        } else {
-            String msg = "received incomplete data for createGroup";
+        if (deviceGroup == null) {
+            String msg = "Received incomplete data for createGroup";
             log.error(msg);
             throw new GroupManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Creating group '" + deviceGroup.getName() + "'");
+        }
         if (deviceGroup == null) {
             throw new GroupManagementException("DeviceGroup cannot be null.", new NullPointerException());
         }
@@ -97,7 +96,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in creating group '" + deviceGroup.getName() + "'";
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -115,15 +114,14 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
     @Override
     public void updateGroup(DeviceGroup deviceGroup, int groupId)
             throws GroupManagementException, GroupAlreadyExistException {
-        if (deviceGroup != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("update group '" + deviceGroup.getName() + "'");
-            }
-        } else {
-            String msg = "received incomplete data for updateGroup";
+        if (deviceGroup == null) {
+            String msg = "Received incomplete data for updateGroup";
             log.error(msg);
             throw new GroupManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("update group '" + deviceGroup.getName() + "'");
+        }
         if (deviceGroup == null) {
             throw new GroupManagementException("DeviceGroup cannot be null.", new NullPointerException());
         }
@@ -147,7 +145,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in updating group '" + deviceGroup.getName() + "'";
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -185,7 +183,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in deleting group: " + groupId;
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -214,7 +212,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getGroup for groupId: " + groupId;
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -228,15 +226,14 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
      */
     @Override
     public DeviceGroup getGroup(String groupName) throws GroupManagementException {
-        if (groupName != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get group by name '" + groupName + "'");
-            }
-        } else {
-            String msg = "received empty groupName for getGroup";
+        if (groupName == null) {
+            String msg = "Received empty groupName for getGroup";
             log.error(msg);
             throw new GroupManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get group by name '" + groupName + "'");
+        }
         DeviceGroup deviceGroup;
         try {
             GroupManagementDAOFactory.openConnection();
@@ -250,7 +247,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getGroup with name " + groupName;
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -278,7 +275,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getGroups";
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -289,15 +286,14 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
 
     @Override
     public PaginationResult getGroups(GroupPaginationRequest request) throws GroupManagementException {
-        if (request != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get groups with pagination " + request.toString());
-            }
-        } else {
-            String msg = "received incomplete data for getGroup";
+        if (request == null) {
+            String msg = "Received incomplete data for getGroup";
             log.error(msg);
             throw new GroupManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get groups with pagination " + request.toString());
+        }
         request = DeviceManagerUtil.validateGroupListPageSize(request);
         List<DeviceGroup> deviceGroups = new ArrayList<>();
         try {
@@ -313,7 +309,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getGroups";
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -327,15 +323,14 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
 
     @Override
     public List<DeviceGroup> getGroups(String username) throws GroupManagementException {
-        if (username != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get groups of owner '" + username + "'");
-            }
-        } else {
-            String msg = "received null user name for getGroups";
+        if (username == null || username.isEmpty()) {
+            String msg = "Received null user name for getGroups";
             log.error(msg);
             throw new GroupManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get groups of owner '" + username + "'");
+        }
         Map<Integer, DeviceGroup> groups = new HashMap<>();
         UserStoreManager userStoreManager;
         try {
@@ -364,7 +359,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(e);
             throw new GroupManagementException(e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getGroups for " + username;
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -374,15 +369,14 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
     }
 
     private List<Integer> getGroupIds(String username) throws GroupManagementException {
-        if (username != null) {
-            if (log.isDebugEnabled()) {
-                log.debug("Get groups Ids of owner '" + username + "'");
-            }
-        } else {
-            String msg = "received empty user name for getGroupIds";
+        if (username == null || username.isEmpty()) {
+            String msg = "Received empty user name for getGroupIds";
             log.error(msg);
             throw new GroupManagementException(msg);
         }
+        if (log.isDebugEnabled()) {
+            log.debug("Get groups Ids of owner '" + username + "'");
+        }
         UserStoreManager userStoreManager;
         List<Integer> deviceGroupIds = new ArrayList<>();
         try {
@@ -405,7 +399,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(e);
             throw new GroupManagementException(e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getGroups for username '" + username + "'";
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -418,7 +412,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
     public PaginationResult getGroups(String currentUser, GroupPaginationRequest request)
             throws GroupManagementException {
         if (currentUser == null || request == null) {
-            String msg = "received incomplete date for getGroups";
+            String msg = "Received incomplete date for getGroups";
             log.error(msg);
             throw new GroupManagementException(msg);
         }
@@ -441,7 +435,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getGroups";
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -481,7 +475,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
 
     private int getGroupCount(GroupPaginationRequest request) throws GroupManagementException {
         if (request == null) {
-            String msg = "received empty request for getGroupCount";
+            String msg = "Received empty request for getGroupCount";
             log.error(msg);
             throw new GroupManagementException(msg);
         }
@@ -501,7 +495,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getGroupCount";
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -514,8 +508,8 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
      */
     @Override
     public int getGroupCount(String username) throws GroupManagementException {
-        if (username == null) {
-            String msg = "received empty user name for getGroupCount";
+        if (username == null || username.isEmpty()) {
+            String msg = "Received empty user name for getGroupCount";
             log.error(msg);
             throw new GroupManagementException(msg);
         }
@@ -546,7 +540,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getGroupCount for username '" + username + "'";
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -601,7 +595,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(e);
             throw new GroupManagementException(e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in manageGroupSharing for groupId: " + groupId;
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -630,7 +624,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getRoles for groupId: " + groupId;
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -666,7 +660,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDevices for groupId: " + groupId;
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -695,7 +689,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getDeviceCount for groupId: " + groupId;
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -741,7 +735,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in addDevices for groupId " + groupId;
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -785,7 +779,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in removeDevice for groupId: " + groupId;
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -821,7 +815,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getGroups for username '" + username + "'";
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         }
@@ -831,7 +825,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
     @Override
     public List<DeviceGroup> getGroups(DeviceIdentifier deviceIdentifier) throws GroupManagementException {
         if (deviceIdentifier == null) {
-            String msg = "received empty device identifier for getGroups";
+            String msg = "Received empty device identifier for getGroups";
             log.error(msg);
             throw new GroupManagementException(msg);
         }
@@ -857,7 +851,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } catch (Exception e) {
-            String msg = "Error occurred";
+            String msg = "Error occurred in getGroups";
             log.error(msg, e);
             throw new GroupManagementException(msg, e);
         } finally {
@@ -887,7 +881,7 @@ public class GroupManagementProviderServiceImpl implements GroupManagementProvid
                 log.error(msg, e);
                 throw new GroupManagementException(msg, e);
             } catch (Exception e) {
-                String msg = "Error occurred";
+                String msg = "Error occurred in createDefaultGroup for groupName '" + groupName + "'";
                 log.error(msg, e);
                 throw new GroupManagementException(msg, e);
             }