FINERACT-942 Added and enforced MutableException Checkstyle

fineract-provider/config/checkstyle/checkstyle.xml

@@ -160,6 +160,7 @@
             <message key="name.invalidPattern"
              value="Method name ''{0}'' must match pattern ''{1}''."/>
         </module>
+          <module name="MutableException"/>
             <module name="WhitespaceAround">
             <property name="allowEmptyConstructors" value="true"/>
             <property name="allowEmptyMethods" value="true"/>
@@ -185,7 +186,7 @@
         < ! - - TODO Checks for Exception Handling Anti-Patterns - - >
         <module name="IllegalCatch"/>
 
-        <module name="MutableException"/>
+
         <module name="com.github.sevntu.checkstyle.checks.coding.AvoidHidingCauseExceptionCheck" />
 
 

fineract-provider/src/main/java/org/apache/fineract/portfolio/client/exception/DuplicateClientIdentifierException.java

@@ -26,14 +26,16 @@ import org.apache.fineract.infrastructure.core.exception.AbstractPlatformDomainR
  */
 public class DuplicateClientIdentifierException extends AbstractPlatformDomainRuleException {
 
-    private Long documentTypeId;
-    private String identifierKey;
+    private final Long documentTypeId;
+    private final String identifierKey;
     private final String identifierType;
 
     public DuplicateClientIdentifierException(final String identifierType) {
         super("error.msg.clientIdentifier.type.duplicate",
                 "Active Client identifier of type " + identifierType + " is already present for this client", identifierType);
         this.identifierType = identifierType;
+        this.identifierKey = null;
+        this.documentTypeId = null;
     }
 
     public DuplicateClientIdentifierException(final Long documentTypeId, final String identifierType, final String identifierKey) {
@@ -51,6 +53,8 @@ public class DuplicateClientIdentifierException extends AbstractPlatformDomainRu
                 + identifierType + " with unique key " + identifierKey, clientName, officeName, identifierType, identifierKey);
         this.identifierType = identifierType;
         this.identifierKey = identifierKey;
+        this.documentTypeId = null;
+
     }
 
     public Long getDocumentTypeId() {