Fix some code issues to pass Sonar quality gate

Author: joschi

cli/src/main/java/org/openapitools/openapidiff/cli/Main.java

@@ -2,6 +2,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import org.apache.commons.cli.CommandLine;
 import org.apache.commons.cli.CommandLineParser;
 import org.apache.commons.cli.DefaultParser;
@@ -100,7 +101,6 @@ public static void main(String... args) {
             .desc("export diff as text in given file")
             .build());
 
-    final String message = "Hello logging!";
     // create the parser
     CommandLineParser parser = new DefaultParser();
     try {
@@ -202,7 +202,7 @@ private static void writeOutput(String output, String outputFile) {
     File file = new File(outputFile);
     logger.debug("Output file: {}", file.getAbsolutePath());
     try {
-      FileUtils.writeStringToFile(file, output);
+      FileUtils.writeStringToFile(file, output, StandardCharsets.UTF_8);
     } catch (IOException e) {
       logger.error("Impossible to write output to file {}", outputFile, e);
       System.exit(2);

core/src/main/java/org/openapitools/openapidiff/core/OpenApiCompare.java

@@ -11,8 +11,8 @@
 
 public class OpenApiCompare {
 
-  private static OpenAPIParser openApiParser = new OpenAPIParser();
-  private static ParseOptions options = new ParseOptions();
+  private static final OpenAPIParser openApiParser = new OpenAPIParser();
+  private static final ParseOptions options = new ParseOptions();
 
   static {
     options.setResolve(true);

core/src/main/java/org/openapitools/openapidiff/core/compare/ApiResponseDiff.java

@@ -14,7 +14,7 @@
 
 /** Created by adarsh.sharma on 04/01/18. */
 public class ApiResponseDiff {
-  private OpenApiDiff openApiDiff;
+  private final OpenApiDiff openApiDiff;
 
   public ApiResponseDiff(OpenApiDiff openApiDiff) {
     this.openApiDiff = openApiDiff;

core/src/main/java/org/openapitools/openapidiff/core/compare/Comparable.java

@@ -10,19 +10,14 @@
 import org.openapitools.openapidiff.core.model.ChangedMediaType;
 import org.openapitools.openapidiff.core.model.DiffContext;
 
-public class ContentDiff implements Comparable<Content> {
+public class ContentDiff {
 
-  private OpenApiDiff openApiDiff;
+  private final OpenApiDiff openApiDiff;
 
   public ContentDiff(OpenApiDiff openApiDiff) {
     this.openApiDiff = openApiDiff;
   }
 
-  @Override
-  public boolean compare(Content left, Content right) {
-    return false;
-  }
-
   public Optional<ChangedContent> diff(Content left, Content right, DiffContext context) {
 
     MapKeyDiff<String, MediaType> mediaTypeDiff = MapKeyDiff.diff(left, right);

core/src/main/java/org/openapitools/openapidiff/core/compare/ContentDiff.java

@@ -13,13 +13,13 @@
 public class ExtensionsDiff {
   private final OpenApiDiff openApiDiff;
 
-  private ServiceLoader<ExtensionDiff> extensionsLoader = ServiceLoader.load(ExtensionDiff.class);
-  private List<ExtensionDiff> extensionsDiff = new ArrayList<>();
+  private final List<ExtensionDiff> extensionsDiff = new ArrayList<>();
 
   public ExtensionsDiff(OpenApiDiff openApiDiff) {
     this.openApiDiff = openApiDiff;
-    this.extensionsLoader.reload();
-    for (ExtensionDiff anExtensionsLoader : this.extensionsLoader) {
+    ServiceLoader<ExtensionDiff> extensionsLoader = ServiceLoader.load(ExtensionDiff.class);
+    extensionsLoader.reload();
+    for (ExtensionDiff anExtensionsLoader : extensionsLoader) {
       extensionsDiff.add(anExtensionsLoader);
     }
   }

core/src/main/java/org/openapitools/openapidiff/core/compare/ExtensionsDiff.java

@@ -14,10 +14,10 @@
 
 /** Created by adarsh.sharma on 28/12/17. */
 public class HeaderDiff extends ReferenceDiffCache<Header, ChangedHeader> {
-  private static RefPointer<Header> refPointer = new RefPointer<>(RefType.HEADERS);
-  private OpenApiDiff openApiDiff;
-  private Components leftComponents;
-  private Components rightComponents;
+  private static final RefPointer<Header> refPointer = new RefPointer<>(RefType.HEADERS);
+  private final OpenApiDiff openApiDiff;
+  private final Components leftComponents;
+  private final Components rightComponents;
 
   public HeaderDiff(OpenApiDiff openApiDiff) {
     this.openApiDiff = openApiDiff;

core/src/main/java/org/openapitools/openapidiff/core/compare/HeaderDiff.java

@@ -13,7 +13,7 @@
 
 /** Created by adarsh.sharma on 28/12/17. */
 public class HeadersDiff {
-  private OpenApiDiff openApiDiff;
+  private final OpenApiDiff openApiDiff;
 
   public HeadersDiff(OpenApiDiff openApiDiff) {
     this.openApiDiff = openApiDiff;

core/src/main/java/org/openapitools/openapidiff/core/compare/HeadersDiff.java

@@ -15,7 +15,7 @@ public class MapKeyDiff<K, V> {
 
   private Map<K, V> increased;
   private Map<K, V> missing;
-  private List<K> sharedKey;
+  private final List<K> sharedKey;
 
   private MapKeyDiff() {
     this.sharedKey = new ArrayList<>();

core/src/main/java/org/openapitools/openapidiff/core/compare/MapKeyDiff.java

@@ -9,9 +9,9 @@
 
 public class MetadataDiff {
 
-  private Components leftComponents;
-  private Components rightComponents;
-  private OpenApiDiff openApiDiff;
+  private final Components leftComponents;
+  private final Components rightComponents;
+  private final OpenApiDiff openApiDiff;
 
   public MetadataDiff(OpenApiDiff openApiDiff) {
     this.openApiDiff = openApiDiff;