chore: Sonarqube improvements

Author: en-milie

src/main/java/com/endava/cats/fuzzer/fields/base/TwoXXorFourXXReplaceStringsFuzzer.java

@@ -40,6 +40,7 @@ protected TwoXXorFourXXReplaceStringsFuzzer(TestCaseListener testCaseListener, F
         this.fieldsIteratorExecutor = fieldsIteratorExecutor;
     }
 
+    @Override
     public void fuzz(FuzzingData data) {
         ResponseCodeFamily expectedResponseCodes = new ResponseCodeFamilyDynamic(List.of("2XX", "4XX"));
         fieldsIteratorExecutor.execute(

src/main/java/com/endava/cats/fuzzer/special/mutators/api/Mutator.java

@@ -36,6 +36,7 @@ public interface Mutator extends Comparable<Mutator> {
      */
     String description();
 
+    @Override
     default int compareTo(Mutator o) {
         return this.getClass().getSimpleName().compareTo(o.getClass().getSimpleName());
     }

src/main/java/com/endava/cats/http/ResponseCodeFamilyDynamic.java

@@ -27,9 +27,10 @@ public List<String> allowedResponseCodes() {
 
     @Override
     public boolean equals(Object o) {
-        if (o == null || getClass() != o.getClass()) return false;
-        ResponseCodeFamilyDynamic that = (ResponseCodeFamilyDynamic) o;
-        return Objects.equals(responseCodes, that.responseCodes);
+        if (o instanceof ResponseCodeFamilyDynamic that) {
+            return Objects.equals(responseCodes, that.responseCodes);
+        }
+        return false;
     }
 
     @Override

src/main/java/com/endava/cats/util/JsonUtils.java

@@ -293,7 +293,7 @@ public static boolean isValidJson(String text) {
             return false;
         }
         try {
-            JSON_STRICT_PARSER.fromJson(text, Object.class);
+            var unused = JSON_STRICT_PARSER.fromJson(text, Object.class);
         } catch (Exception e) {
             return false;
         }