diff --git a/checkstyle/src/main/resources/cps-java-style.xml b/checkstyle/src/main/resources/cps-java-style.xml
index 67b2863..d10484c 100644
--- a/checkstyle/src/main/resources/cps-java-style.xml
+++ b/checkstyle/src/main/resources/cps-java-style.xml
@@ -32,4 +32,4 @@
         </module>
         <module name="UnusedImports"/>
     </module>
-</module>
\ No newline at end of file
+</module>
diff --git a/cps-application/src/main/resources/application.yml b/cps-application/src/main/resources/application.yml
index b97eaba..05b0d09 100644
--- a/cps-application/src/main/resources/application.yml
+++ b/cps-application/src/main/resources/application.yml
@@ -190,7 +190,7 @@
 ncmp:
     policy-executor:
         enabled: ${POLICY_SERVICE_ENABLED:false}
-        defaultDecision: "allow"
+        defaultDecision: ${POLICY_SERVICE_DEFAULT_DECISION:"allow"}
         server:
             address: ${POLICY_SERVICE_URL:http://policy-executor-stub}
             port: ${POLICY_SERVICE_PORT:8093}
diff --git a/cps-dependencies/pom.xml b/cps-dependencies/pom.xml
index adef903..611ae74 100644
--- a/cps-dependencies/pom.xml
+++ b/cps-dependencies/pom.xml
@@ -126,7 +126,12 @@
             <dependency>
                 <groupId>com.github.spotbugs</groupId>
                 <artifactId>spotbugs</artifactId>
-                <version>4.2.3</version>
+                <version>4.8.6</version>
+            </dependency>
+            <dependency>
+                <groupId>com.github.spotbugs</groupId>
+                <artifactId>spotbugs-annotations</artifactId>
+                <version>3.1.3</version>
             </dependency>
             <dependency>
                 <groupId>com.google.code.findbugs</groupId>
diff --git a/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyRestExceptionHandlerSpec.groovy b/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyRestExceptionHandlerSpec.groovy
index 9d36d10..e87acac 100644
--- a/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyRestExceptionHandlerSpec.groovy
+++ b/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyRestExceptionHandlerSpec.groovy
@@ -129,19 +129,19 @@
         then: 'an HTTP response is returned with correct message and details'
             assertTestResponse(response, expectedErrorCode, expectedErrorMessage, expectedErrorDetails)
         where:
-            scenario                | exception                                                           || expectedErrorCode     | expectedErrorMessage        | expectedErrorDetails
-            'CPS'                   | new CpsException(sampleErrorMessage, sampleErrorDetails)            || INTERNAL_SERVER_ERROR | sampleErrorMessage          | sampleErrorDetails
-            'NCMP-server'           | new ServerNcmpException(sampleErrorMessage, sampleErrorDetails)     || INTERNAL_SERVER_ERROR | sampleErrorMessage          | null
-            'DMI Request'           | new DmiRequestException(sampleErrorMessage, sampleErrorDetails)     || BAD_REQUEST           | sampleErrorMessage          | null
-            'Invalid Operation'     | new InvalidOperationException('some reason')                        || BAD_REQUEST           | 'some reason'               | null
-            'Unsupported Operation' | new OperationNotSupportedException('not yet')                       || BAD_REQUEST           | 'not yet'                   | null
-            'DataNode Validation'   | new DataNodeNotFoundException('myDataspaceName', 'myAnchorName')    || NOT_FOUND             | 'DataNode not found'        | null
-            'other'                 | new IllegalStateException(sampleErrorMessage)                       || INTERNAL_SERVER_ERROR | sampleErrorMessage          | null
-            'Data Node Not Found'   | new DataNodeNotFoundException('myDataspaceName', 'myAnchorName')    || NOT_FOUND             | 'DataNode not found'        | 'DataNode not found'
-            'Existing entry'        | new AlreadyDefinedException('name',null)                            || CONFLICT              | 'Already defined exception' | 'name already exists'
-            'Existing entries'      | AlreadyDefinedException.forDataNodes(['A', 'B'], 'myAnchorName')    || CONFLICT              | 'Already defined exception' | '2 data node(s) already exist'
-            'Operation too large'   | new PayloadTooLargeException(sampleErrorMessage)                    || PAYLOAD_TOO_LARGE     | sampleErrorMessage          | 'Check logs'
-            'Policy Executor'       | new PolicyExecutorException(sampleErrorMessage, sampleErrorDetails) || CONFLICT              | sampleErrorMessage          | sampleErrorDetails
+            scenario                | exception                                                                 || expectedErrorCode     | expectedErrorMessage        | expectedErrorDetails
+            'CPS'                   | new CpsException(sampleErrorMessage, sampleErrorDetails)                  || INTERNAL_SERVER_ERROR | sampleErrorMessage          | sampleErrorDetails
+            'NCMP-server'           | new ServerNcmpException(sampleErrorMessage, sampleErrorDetails)           || INTERNAL_SERVER_ERROR | sampleErrorMessage          | null
+            'DMI Request'           | new DmiRequestException(sampleErrorMessage, sampleErrorDetails)           || BAD_REQUEST           | sampleErrorMessage          | null
+            'Invalid Operation'     | new InvalidOperationException('some reason')                              || BAD_REQUEST           | 'some reason'               | null
+            'Unsupported Operation' | new OperationNotSupportedException('not yet')                             || BAD_REQUEST           | 'not yet'                   | null
+            'DataNode Validation'   | new DataNodeNotFoundException('myDataspaceName', 'myAnchorName')          || NOT_FOUND             | 'DataNode not found'        | null
+            'other'                 | new IllegalStateException(sampleErrorMessage)                             || INTERNAL_SERVER_ERROR | sampleErrorMessage          | null
+            'Data Node Not Found'   | new DataNodeNotFoundException('myDataspaceName', 'myAnchorName')          || NOT_FOUND             | 'DataNode not found'        | 'DataNode not found'
+            'Existing entry'        | new AlreadyDefinedException('name',null)                                  || CONFLICT              | 'Already defined exception' | 'name already exists'
+            'Existing entries'      | AlreadyDefinedException.forDataNodes(['A', 'B'], 'myAnchorName')          || CONFLICT              | 'Already defined exception' | '2 data node(s) already exist'
+            'Operation too large'   | new PayloadTooLargeException(sampleErrorMessage)                          || PAYLOAD_TOO_LARGE     | sampleErrorMessage          | 'Check logs'
+            'Policy Executor'       | new PolicyExecutorException(sampleErrorMessage, sampleErrorDetails, null) || CONFLICT              | sampleErrorMessage          | sampleErrorDetails
     }
 
     def 'Post request with exception returns correct HTTP Status.'() {
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/exceptions/NcmpException.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/exceptions/NcmpException.java
index 6754965..3c81d0f 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/exceptions/NcmpException.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/exceptions/NcmpException.java
@@ -39,7 +39,18 @@
      * @param details the error details
      */
     public NcmpException(final String message, final String details) {
-        super(message);
+        this(message, details, null);
+    }
+
+    /**
+     * Constructor with cause.
+     *
+     * @param message the error message
+     * @param details the error details
+     * @param cause the cause of the exception
+     */
+    public NcmpException(final String message, final String details, final Throwable cause) {
+        super(message, cause);
         this.details = details;
     }
 
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/exceptions/PolicyExecutorException.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/exceptions/PolicyExecutorException.java
index 333c122..bb753b8 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/exceptions/PolicyExecutorException.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/exceptions/PolicyExecutorException.java
@@ -35,8 +35,9 @@
      *
      * @param message response message
      * @param details response details
+     * @param cause   the cause of the exception
      */
-    public PolicyExecutorException(final String message, final String details) {
-        super(message, details);
+    public PolicyExecutorException(final String message, final String details, final Throwable cause) {
+        super(message, details, cause);
     }
 }
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/data/policyexecutor/PolicyExecutor.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/data/policyexecutor/PolicyExecutor.java
index caed28a..af43318 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/data/policyexecutor/PolicyExecutor.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/data/policyexecutor/PolicyExecutor.java
@@ -23,6 +23,7 @@
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import java.net.UnknownHostException;
 import java.time.Duration;
 import java.time.temporal.ChronoUnit;
 import java.util.Collections;
@@ -45,6 +46,7 @@
 import org.springframework.stereotype.Service;
 import org.springframework.web.reactive.function.BodyInserters;
 import org.springframework.web.reactive.function.client.WebClient;
+import org.springframework.web.reactive.function.client.WebClientResponseException;
 
 @Slf4j
 @Service
@@ -71,6 +73,8 @@
 
     private final ObjectMapper objectMapper;
 
+    private static final Throwable NO_ERROR = null;
+
     /**
      * Use the Policy Executor to check permission for a cm write operation.
      * Wil throw an exception when the operation is not permitted (work in progress)
@@ -88,26 +92,20 @@
                                 final String changeRequestAsJson) {
         log.trace("Policy Executor Enabled: {}", enabled);
         if (enabled) {
-            ResponseEntity<JsonNode> responseEntity = null;
             try {
-                responseEntity =
-                    getPolicyExecutorResponse(yangModelCmHandle, operationType, authorization, resourceIdentifier,
-                        changeRequestAsJson);
-            } catch (final RuntimeException runtimeException) {
-                processException(runtimeException);
-            }
-            if (responseEntity == null) {
-                log.warn("No valid response from Policy Executor, ignored");
-                return;
-            }
-            if (responseEntity.getStatusCode().is2xxSuccessful()) {
-                if (responseEntity.getBody() == null) {
+                final ResponseEntity<JsonNode> responseEntity = getPolicyExecutorResponse(yangModelCmHandle,
+                                                                                          operationType,
+                                                                                          authorization,
+                                                                                          resourceIdentifier,
+                                                                                          changeRequestAsJson);
+                final JsonNode responseBody = responseEntity.getBody();
+                if (responseBody == null) {
                     log.warn("No valid response body from Policy Executor, ignored");
                     return;
                 }
-                processSuccessResponse(responseEntity.getBody());
-            } else {
-                processNon2xxResponse(responseEntity.getStatusCode().value());
+                processSuccessResponse(responseBody);
+            } catch (final RuntimeException runtimeException) {
+                processException(runtimeException);
             }
         }
     }
@@ -173,35 +171,17 @@
             .block();
     }
 
-    private void processNon2xxResponse(final int httpStatusCode) {
-        processFallbackResponse("Policy Executor returned HTTP Status code " + httpStatusCode + ".");
-    }
-
-    private void processException(final RuntimeException runtimeException) {
-        if (runtimeException.getCause() instanceof TimeoutException) {
-            processFallbackResponse("Policy Executor request timed out.");
-        } else {
-            log.warn("Request to Policy Executor failed with unexpected exception", runtimeException);
-            throw runtimeException;
-        }
-    }
-
-    private void processFallbackResponse(final String message) {
-        final String decisionId = "N/A";
-        final String decision = defaultDecision;
-        final String warning = message + " Falling back to configured default decision: " + defaultDecision;
-        log.warn(warning);
-        processDecision(decisionId, decision, warning);
-    }
-
     private static void processSuccessResponse(final JsonNode responseBody) {
         final String decisionId = responseBody.path("decisionId").asText("unknown id");
         final String decision = responseBody.path("decision").asText("unknown");
         final String messageFromPolicyExecutor = responseBody.path("message").asText();
-        processDecision(decisionId, decision, messageFromPolicyExecutor);
+        processDecision(decisionId, decision, messageFromPolicyExecutor, NO_ERROR);
     }
 
-    private static void processDecision(final String decisionId, final String decision, final String details) {
+    private static void processDecision(final String decisionId,
+                                        final String decision,
+                                        final String details,
+                                        final Throwable optionalCauseOfError) {
         log.trace("Policy Executor decision id: {} ", decisionId);
         if ("allow".equals(decision)) {
             log.trace("Operation allowed.");
@@ -209,8 +189,37 @@
             log.warn("Policy Executor decision: {}", decision);
             log.warn("Policy Executor message: {}", details);
             final String message = "Operation not allowed. Decision id " + decisionId + " : " + decision;
-            throw new PolicyExecutorException(message, details);
+            throw new PolicyExecutorException(message, details, optionalCauseOfError);
         }
     }
 
+    private void processException(final RuntimeException runtimeException) {
+        if (runtimeException instanceof WebClientResponseException) {
+            final WebClientResponseException webClientResponseException = (WebClientResponseException) runtimeException;
+            final int httpStatusCode = webClientResponseException.getStatusCode().value();
+            processFallbackResponse("Policy Executor returned HTTP Status code " + httpStatusCode + ".",
+                webClientResponseException);
+        } else {
+            final Throwable cause = runtimeException.getCause();
+            if (cause instanceof TimeoutException) {
+                processFallbackResponse("Policy Executor request timed out.", cause);
+            } else if (cause instanceof UnknownHostException) {
+                final String message
+                    = String.format("Cannot connect to Policy Executor (%s:%s).", serverAddress, serverPort);
+                processFallbackResponse(message, cause);
+            } else {
+                log.warn("Request to Policy Executor failed with unexpected exception", runtimeException);
+                throw runtimeException;
+            }
+        }
+    }
+
+    private void processFallbackResponse(final String message, final Throwable cause) {
+        final String decisionId = "N/A";
+        final String decision = defaultDecision;
+        final String warning = message + " Falling back to configured default decision: " + defaultDecision;
+        log.warn(warning);
+        processDecision(decisionId, decision, warning, cause);
+    }
+
 }
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/sync/lcm/LcmEventType.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/sync/lcm/LcmEventType.java
index 4bc2f10..1d4e3c8 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/sync/lcm/LcmEventType.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/sync/lcm/LcmEventType.java
@@ -26,10 +26,10 @@
 
     private final String eventName;
 
-    private final String eventTypeTemplate = "org.onap.ncmp.cmhandle-lcm-event.%s";
+    private static final String EVENT_TYPE_TEMPLATE = "org.onap.ncmp.cmhandle-lcm-event.%s";
 
     LcmEventType(final String eventName) {
-        this.eventName = String.format(eventTypeTemplate, eventName);
+        this.eventName = String.format(EVENT_TYPE_TEMPLATE, eventName);
     }
 
     public String getEventType() {
diff --git a/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/data/policyexecutor/PolicyExecutorSpec.groovy b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/data/policyexecutor/PolicyExecutorSpec.groovy
index 46c0dde..33dcf5d 100644
--- a/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/data/policyexecutor/PolicyExecutorSpec.groovy
+++ b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/data/policyexecutor/PolicyExecutorSpec.groovy
@@ -33,6 +33,7 @@
 import org.springframework.http.HttpStatus
 import org.springframework.http.ResponseEntity
 import org.springframework.web.reactive.function.client.WebClient
+import org.springframework.web.reactive.function.client.WebClientResponseException
 import reactor.core.publisher.Mono
 import spock.lang.Specification
 
@@ -59,6 +60,8 @@
     def setup() {
         setupLogger()
         objectUnderTest.enabled = true
+        objectUnderTest.serverAddress = 'some host'
+        objectUnderTest.serverPort = 'some port'
         mockWebClient.post() >> mockRequestBodyUriSpec
         mockRequestBodyUriSpec.uri(*_) >> mockRequestBodyUriSpec
         mockRequestBodyUriSpec.header(*_) >> mockRequestBodyUriSpec
@@ -95,8 +98,8 @@
     }
 
     def 'Permission check with non-2xx response and "allow" default decision.'() {
-        given: 'other http response'
-            mockResponse([], HttpStatus.I_AM_A_TEAPOT)
+        given: 'non-2xx http response'
+            mockErrorResponse()
         and: 'the configured default decision is "allow"'
             objectUnderTest.defaultDecision = 'allow'
         when: 'permission is checked for an operation'
@@ -106,8 +109,8 @@
     }
 
     def 'Permission check with non-2xx response and "other" default decision.'() {
-        given: 'other http response'
-            mockResponse([], HttpStatus.I_AM_A_TEAPOT)
+        given: 'non-2xx http response'
+            def webClientException = mockErrorResponse()
         and: 'the configured default decision is NOT "allow"'
             objectUnderTest.defaultDecision = 'deny by default'
         when: 'permission is checked for an operation'
@@ -116,25 +119,23 @@
             def thrownException = thrown(PolicyExecutorException)
             assert thrownException.message == 'Operation not allowed. Decision id N/A : deny by default'
             assert thrownException.details == 'Policy Executor returned HTTP Status code 418. Falling back to configured default decision: deny by default'
+        and: 'the cause is the original web client exception'
+            assert thrownException.cause == webClientException
     }
 
     def 'Permission check with invalid response from Policy Executor.'() {
         given: 'invalid response from Policy executor'
-            mockResponseSpec.toEntity(*_) >> invalidResponse
+            mockResponseSpec.toEntity(*_) >> Mono.just(new ResponseEntity<>(null, HttpStatus.OK))
         when: 'permission is checked for an operation'
             objectUnderTest.checkPermission(new YangModelCmHandle(), CREATE, 'my credentials', 'my resource', someValidJson)
         then: 'system logs the expected message'
-            assert getLogEntry(1) == expectedMessage
-        where: 'following invalid responses are received'
-            invalidResponse                                      || expectedMessage
-            Mono.empty()                                         || 'No valid response from Policy Executor, ignored'
-            Mono.just(new ResponseEntity<>(null, HttpStatus.OK)) || 'No valid response body from Policy Executor, ignored'
+            assert getLogEntry(1) == 'No valid response body from Policy Executor, ignored'
     }
 
     def 'Permission check with timeout exception.'() {
         given: 'a timeout during the request'
-            def cause = new TimeoutException()
-            mockResponseSpec.toEntity(*_) >> { throw new RuntimeException(cause) }
+            def timeoutException = new TimeoutException()
+            mockResponseSpec.toEntity(*_) >> { throw new RuntimeException(timeoutException) }
         and: 'the configured default decision is NOT "allow"'
             objectUnderTest.defaultDecision = 'deny by default'
         when: 'permission is checked for an operation'
@@ -143,6 +144,39 @@
             def thrownException = thrown(PolicyExecutorException)
             assert thrownException.message == 'Operation not allowed. Decision id N/A : deny by default'
             assert thrownException.details == 'Policy Executor request timed out. Falling back to configured default decision: deny by default'
+        and: 'the cause is the original time out exception'
+            assert thrownException.cause == timeoutException
+    }
+
+    def 'Permission check with unknown host.'() {
+        given: 'a unknown host exception during the request'
+            def unknownHostException = new UnknownHostException()
+            mockResponseSpec.toEntity(*_) >> { throw new RuntimeException(unknownHostException) }
+        and: 'the configured default decision is NOT "allow"'
+            objectUnderTest.defaultDecision = 'deny by default'
+        when: 'permission is checked for an operation'
+            objectUnderTest.checkPermission(new YangModelCmHandle(), CREATE, 'my credentials', 'my resource', someValidJson)
+        then: 'Policy Executor exception is thrown'
+            def thrownException = thrown(PolicyExecutorException)
+            assert thrownException.message == 'Operation not allowed. Decision id N/A : deny by default'
+            assert thrownException.details == 'Cannot connect to Policy Executor (some host:some port). Falling back to configured default decision: deny by default'
+        and: 'the cause is the original unknown host exception'
+            assert thrownException.cause == unknownHostException
+    }
+
+    def 'Permission check with #scenario exception and default decision "allow".'() {
+        given: 'a #scenario exception during the request'
+            mockResponseSpec.toEntity(*_) >> { throw new RuntimeException(cause)}
+        and: 'the configured default decision is "allow"'
+            objectUnderTest.defaultDecision = 'allow'
+        when: 'permission is checked for an operation'
+            objectUnderTest.checkPermission(new YangModelCmHandle(), CREATE, 'my credentials', 'my resource', someValidJson)
+        then: 'no exception is thrown'
+            noExceptionThrown()
+        where: 'the following exceptions are thrown during the request'
+            scenario       | cause
+            'timeout'      | new TimeoutException()
+            'unknown host' | new UnknownHostException()
     }
 
     def 'Permission check with other runtime exception.'() {
@@ -180,6 +214,13 @@
         mockResponseSpec.toEntity(*_) >> mono
     }
 
+    def mockErrorResponse() {
+        def webClientResponseException = Mock(WebClientResponseException)
+        webClientResponseException.getStatusCode() >> HttpStatus.I_AM_A_TEAPOT
+        mockResponseSpec.toEntity(*_) >> { throw webClientResponseException }
+        return webClientResponseException
+    }
+
     def setupLogger() {
         def logger = LoggerFactory.getLogger(PolicyExecutor)
         logger.setLevel(Level.TRACE)
diff --git a/cps-parent/pom.xml b/cps-parent/pom.xml
index 430f4b5..cdd74fd 100644
--- a/cps-parent/pom.xml
+++ b/cps-parent/pom.xml
@@ -154,12 +154,12 @@
                 <plugin>
                     <groupId>com.github.spotbugs</groupId>
                     <artifactId>spotbugs-maven-plugin</artifactId>
-                    <version>4.4.2</version>
+                    <version>4.8.6.4</version>
                     <dependencies>
                         <dependency>
                             <groupId>com.github.spotbugs</groupId>
                             <artifactId>spotbugs</artifactId>
-                            <version>4.2.3</version>
+                            <version>4.8.6</version>
                         </dependency>
                         <dependency>
                             <groupId>${project.groupId}</groupId>
diff --git a/cps-ri/pom.xml b/cps-ri/pom.xml
index 57e6528..edbdb62 100644
--- a/cps-ri/pom.xml
+++ b/cps-ri/pom.xml
@@ -68,6 +68,11 @@
             <artifactId>postgresql</artifactId>
             <version>${postgres.version}</version>
         </dependency>
+        <!-- Disable SpotBug Rules -->
+        <dependency>
+            <groupId>com.github.spotbugs</groupId>
+            <artifactId>spotbugs-annotations</artifactId>
+        </dependency>
         <!-- Add Hibernate support for Postgres datatype JSONB and Postgres arrays -->
         <dependency>
             <groupId>io.hypersistence</groupId>
diff --git a/cps-ri/src/main/java/org/onap/cps/ri/repository/ModuleReferenceRepositoryImpl.java b/cps-ri/src/main/java/org/onap/cps/ri/repository/ModuleReferenceRepositoryImpl.java
index c160fb1..281a33d 100644
--- a/cps-ri/src/main/java/org/onap/cps/ri/repository/ModuleReferenceRepositoryImpl.java
+++ b/cps-ri/src/main/java/org/onap/cps/ri/repository/ModuleReferenceRepositoryImpl.java
@@ -20,6 +20,7 @@
 
 package org.onap.cps.ri.repository;
 
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import jakarta.persistence.EntityManager;
 import jakarta.persistence.PersistenceContext;
 import jakarta.persistence.Query;
@@ -118,6 +119,7 @@
         query.setParameter(4, dataspaceName);
     }
 
+    @SuppressFBWarnings(value = "VA_FORMAT_STRING_USES_NEWLINE", justification = "no \n in string just in file format")
     private String buildModuleReferencesSqlQuery(final String parentFragmentClause, final String childFragmentClause) {
         return """
                 WITH Fragment AS (
diff --git a/cps-service/pom.xml b/cps-service/pom.xml
index 2a9c75f..8c350c1 100644
--- a/cps-service/pom.xml
+++ b/cps-service/pom.xml
@@ -64,6 +64,11 @@
       <groupId>com.github.ben-manes.caffeine</groupId>
       <artifactId>caffeine</artifactId>
     </dependency>
+    <!-- Disable SpotBug Rules -->
+    <dependency>
+      <groupId>com.github.spotbugs</groupId>
+      <artifactId>spotbugs-annotations</artifactId>
+    </dependency>
     <dependency>
       <!-- For parsing JSON object -->
       <groupId>com.google.code.gson</groupId>
@@ -139,6 +144,7 @@
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-api</artifactId>
     </dependency>
+
     <!-- T E S T   D E P E N D E N C I E S -->
     <dependency>
       <groupId>org.codehaus.groovy</groupId>
diff --git a/cps-service/src/main/java/org/onap/cps/utils/YangParserHelper.java b/cps-service/src/main/java/org/onap/cps/utils/YangParserHelper.java
index 5971645..232ea74 100644
--- a/cps-service/src/main/java/org/onap/cps/utils/YangParserHelper.java
+++ b/cps-service/src/main/java/org/onap/cps/utils/YangParserHelper.java
@@ -22,6 +22,7 @@
 
 import com.google.gson.JsonSyntaxException;
 import com.google.gson.stream.JsonReader;
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import java.io.IOException;
 import java.io.StringReader;
 import java.net.URISyntaxException;
@@ -127,6 +128,7 @@
         return dataContainerNodeBuilder.build();
     }
 
+    @SuppressFBWarnings(value = "DCN_NULLPOINTER_EXCEPTION", justification = "Problem originates in 3PP code")
     private ContainerNode parseXmlData(final String xmlData,
                                        final SchemaContext schemaContext,
                                        final String parentNodeXpath) {
diff --git a/docker-compose/config/nginx/nginx.conf b/docker-compose/config/nginx/nginx.conf
index 61fed51..7d6b997 100644
--- a/docker-compose/config/nginx/nginx.conf
+++ b/docker-compose/config/nginx/nginx.conf
@@ -22,6 +22,7 @@
     upstream cps-and-ncmp {
         least_conn;
         server docker-compose-cps-and-ncmp-1:8080;
+        ### DEBUG: Disable next line for easier debugging on 1 instance (see also docker-compose.yml)
         server docker-compose-cps-and-ncmp-2:8080;
     }
 
diff --git a/docker-compose/docker-compose.yml b/docker-compose/docker-compose.yml
index 1e47d47..fd1df38 100644
--- a/docker-compose/docker-compose.yml
+++ b/docker-compose/docker-compose.yml
@@ -23,6 +23,7 @@
   ### docker-compose --profile dmi-stub --profile tracing up -d -> run CPS with stubbed dmi-plugin (for open telemetry tracing testing make ONAP_TRACING_ENABLED "true" later "http://localhost:16686" can be accessed from browser)
   ### docker-compose --profile dmi-stub --profile policy-executor-stub up -d -> run CPS with stubbed dmi-plugin and policy executor stub (for policy executor service testing make POLICY_SERVICE_ENABLED "true")
   ### to disable notifications make notification.enabled to false & comment out kafka/zookeeper services ###
+  ### DEBUG: Look for '### DEBUG' comments to enable CPS-NCMP debugging
 
   dbpostgresql:
     container_name: dbpostgresql
@@ -60,10 +61,14 @@
       ONAP_OTEL_SAMPLER_JAEGER_REMOTE_ENDPOINT: http://jaeger-service:14250
       ONAP_OTEL_EXPORTER_ENDPOINT: http://jaeger-service:4317
       POLICY_SERVICE_ENABLED: 'false'
+      POLICY_SERVICE_DEFAULT_DECISION: 'deny from env'
+      ### DEBUG: Uncomment next line to enable java debugging
+      ### DEBUG: JAVA_TOOL_OPTIONS: -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5005
     restart: unless-stopped
     depends_on:
       - dbpostgresql
     deploy:
+      ### DEBUG: For easier debugging use just 1 instance (also update docker-compose/config/nginx/nginx.conf !)
       replicas: 2
       resources:
         reservations:
@@ -72,6 +77,9 @@
         limits:
           cpus: '3'
           memory: 3G
+    ### DEBUG: Uncomment next 2 lines to enable java debugging (ensure 'ports' aligns with 'deploy')
+    ### DEBUG ports:
+    ### DEBUG  - ${CPS_CORE_DEBUG_PORT:-5005}:5005
 
   nginx:
     container_name: nginx-loadbalancer
diff --git a/integration-test/src/test/groovy/org/onap/cps/integration/base/PolicyDispatcher.groovy b/integration-test/src/test/groovy/org/onap/cps/integration/base/PolicyDispatcher.groovy
index c93a527..b08d1c1 100644
--- a/integration-test/src/test/groovy/org/onap/cps/integration/base/PolicyDispatcher.groovy
+++ b/integration-test/src/test/groovy/org/onap/cps/integration/base/PolicyDispatcher.groovy
@@ -20,15 +20,14 @@
 
 package org.onap.cps.integration.base
 
-
 import okhttp3.mockwebserver.Dispatcher
 import okhttp3.mockwebserver.MockResponse
 import okhttp3.mockwebserver.RecordedRequest
-import org.springframework.beans.factory.annotation.Value
 import org.springframework.http.HttpHeaders
 import org.springframework.http.HttpStatus
 import org.springframework.http.MediaType
 import org.testcontainers.shaded.com.fasterxml.jackson.databind.ObjectMapper
+
 import java.util.concurrent.TimeUnit
 
 /**
diff --git a/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/PolicyExecutorIntegrationSpec.groovy b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/PolicyExecutorIntegrationSpec.groovy
index 1d4d19b..56d4bfa 100644
--- a/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/PolicyExecutorIntegrationSpec.groovy
+++ b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/PolicyExecutorIntegrationSpec.groovy
@@ -68,7 +68,7 @@
             'accepted cm handle'    | 'ch-1'   | 'mock expects "ABC"'  || 201                  || 'allow'
             'un-accepted cm handle' | 'ch-2'   | 'mock expects "ABC"'  || 409                  || 'deny from mock server (dispatcher)'
             'timeout'               | 'ch-3'   | 'mock expects "ABC"'  || 409                  || 'test default decision'
-            'invalid authorization' | 'ch-1'   | 'something else'      || 500                  || '401 Unauthorized from POST http://localhost:8790/policy-executor/api/v1/execute'
+            'invalid authorization' | 'ch-1'   | 'something else'      || 409                  || 'test default decision'
     }
 
 }
diff --git a/policy-executor-stub/src/main/java/org/onap/cps/policyexecutor/stub/controller/PolicyExecutorStubController.java b/policy-executor-stub/src/main/java/org/onap/cps/policyexecutor/stub/controller/PolicyExecutorStubController.java
index cdd26c9..88073c0 100644
--- a/policy-executor-stub/src/main/java/org/onap/cps/policyexecutor/stub/controller/PolicyExecutorStubController.java
+++ b/policy-executor-stub/src/main/java/org/onap/cps/policyexecutor/stub/controller/PolicyExecutorStubController.java
@@ -41,9 +41,11 @@
 @Slf4j
 public class PolicyExecutorStubController implements PolicyExecutorApi {
 
+    private final Sleeper sleeper;
     private final ObjectMapper objectMapper;
     private static final Pattern ERROR_CODE_PATTERN = Pattern.compile("(\\d{3})");
     private int decisionCounter = 0;
+    private static int slowResponseTimeInSeconds = 40;
 
     @Override
     public ResponseEntity<PolicyExecutionResponse> executePolicyAction(
@@ -85,7 +87,14 @@
         final String decisionId = String.valueOf(++decisionCounter);
         final String decision;
         final String message;
-
+        if (targetIdentifier.toLowerCase(Locale.getDefault()).contains("slow")) {
+            try {
+                sleeper.haveALittleRest(slowResponseTimeInSeconds);
+            } catch (final InterruptedException e) {
+                log.trace("Sleep interrupted, re-interrupting the thread");
+                Thread.currentThread().interrupt(); // Re-interrupt the thread
+            }
+        }
         if (targetIdentifier.toLowerCase(Locale.getDefault()).contains("cps-is-great")) {
             decision = "allow";
             message = "All good";
diff --git a/policy-executor-stub/src/main/java/org/onap/cps/policyexecutor/stub/controller/Sleeper.java b/policy-executor-stub/src/main/java/org/onap/cps/policyexecutor/stub/controller/Sleeper.java
new file mode 100644
index 0000000..8f904cc
--- /dev/null
+++ b/policy-executor-stub/src/main/java/org/onap/cps/policyexecutor/stub/controller/Sleeper.java
@@ -0,0 +1,35 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2024 Nordix Foundation
+ *  ================================================================================
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  SPDX-License-Identifier: Apache-2.0
+ *  ============LICENSE_END=========================================================
+ */
+
+package org.onap.cps.policyexecutor.stub.controller;
+
+import java.util.concurrent.TimeUnit;
+import org.springframework.stereotype.Service;
+
+/**
+ * This class is a successfull experiment to extract out sleep functionality so the interrupted exception handling can
+ * be covered with a test (e.g. using spy ion Sleeper) and help to get too 100% code coverage.
+ */
+@Service
+public class Sleeper {
+    public void haveALittleRest(final int timeInSeconds) throws InterruptedException {
+        TimeUnit.SECONDS.sleep(timeInSeconds);
+    }
+}
diff --git a/policy-executor-stub/src/test/groovy/org/onap/cps/policyexecutor/stub/controller/PolicyExecutorStubControllerSpec.groovy b/policy-executor-stub/src/test/groovy/org/onap/cps/policyexecutor/stub/controller/PolicyExecutorStubControllerSpec.groovy
index 064e023..44460da 100644
--- a/policy-executor-stub/src/test/groovy/org/onap/cps/policyexecutor/stub/controller/PolicyExecutorStubControllerSpec.groovy
+++ b/policy-executor-stub/src/test/groovy/org/onap/cps/policyexecutor/stub/controller/PolicyExecutorStubControllerSpec.groovy
@@ -25,6 +25,7 @@
 import org.onap.cps.policyexecutor.stub.model.PolicyExecutionRequest
 import org.onap.cps.policyexecutor.stub.model.PolicyExecutionResponse
 import org.onap.cps.policyexecutor.stub.model.Request
+import org.spockframework.spring.SpringBean
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest
 import org.springframework.http.HttpStatus
@@ -43,8 +44,15 @@
     @Autowired
     ObjectMapper objectMapper
 
+    @SpringBean
+    Sleeper sleeper = Spy()
+
     def url = '/policy-executor/api/v1/some-action'
 
+    def setup() {
+        PolicyExecutorStubController.slowResponseTimeInSeconds = 1
+    }
+
     def 'Execute policy action.'() {
         given: 'a policy execution request with target: #targetIdentifier'
             def requestBody = createRequestBody(targetIdentifier)
@@ -66,6 +74,7 @@
             targetIdentifier        || expectedDecsisonId | expectedDecision | expectedMessage
             'some fdn'              || '1'                | 'deny'           | "Only FDNs containing 'cps-is-great' are allowed"
             'fdn with cps-is-great' || '2'                | 'allow'          | 'All good'
+            'slow'                  || '3'                | 'deny'           | "Only FDNs containing 'cps-is-great' are allowed"
     }
 
     def 'Execute policy action with a HTTP error code.'() {
@@ -118,6 +127,19 @@
             assert response.status == HttpStatus.BAD_REQUEST.value()
     }
 
+    def 'Execute policy action with interrupted exception during slow response.'() {
+        given: 'a policy execution request with target: "slow"'
+            def requestBody = createRequestBody('slow')
+            sleeper.haveALittleRest(_) >> { throw new InterruptedException() }
+        when: 'request is posted'
+            mockMvc.perform(post(url)
+                .header('Authorization','some string')
+                .contentType(MediaType.APPLICATION_JSON)
+                .content(requestBody))
+        then: 'response status is Bad Request'
+            noExceptionThrown()
+    }
+
     def 'Execute policy action with missing or invalid attributes.'() {
         given: 'a policy execution request with decisionType=#decisionType, schema=#schema, targetIdentifier=#targetIdentifier'
             def requestBody = createRequestBody(decisionType, schema, targetIdentifier)