Fix the disable failier of the authenticator

components/identity-extensions/backend-oauth-authenticator/src/main/java/org/wso2/carbon/identity/authenticator/backend/oauth/OauthAuthenticator.java

@@ -59,6 +59,7 @@ public class OauthAuthenticator implements CarbonServerAuthenticator {
      */
     public boolean isHandle(MessageContext messageContext) {
         HttpServletRequest httpServletRequest = getHttpRequest(messageContext);
+        if(httpServletRequest != null) {
             String headerValue = httpServletRequest.getHeader(HTTPConstants.HEADER_AUTHORIZATION);
             if (headerValue != null && !headerValue.trim().isEmpty()) {
                 String[] headerPart = headerValue.trim().split(OauthAuthenticatorConstants.SPLITING_CHARACTOR);
@@ -68,6 +69,7 @@ public class OauthAuthenticator implements CarbonServerAuthenticator {
             } else if (httpServletRequest.getParameter(OauthAuthenticatorConstants.BEARER_TOKEN_IDENTIFIER) != null) {
                 return true;
             }
+        }
         return false;
     }
 
@@ -134,7 +136,10 @@ public class OauthAuthenticator implements CarbonServerAuthenticator {
      * @return boolean true for enable or otherwise for disable status.
      */
     public boolean isDisabled() {
-        return false;
+        AuthenticatorsConfiguration authenticatorsConfiguration = AuthenticatorsConfiguration.getInstance();
+        AuthenticatorsConfiguration.AuthenticatorConfig authenticatorConfig = authenticatorsConfiguration.
+                getAuthenticatorConfig(OauthAuthenticatorConstants.AUTHENTICATOR_NAME);
+        return authenticatorConfig.isDisabled();
     }
 
     /**