refactor: address IntelliJ QAPlug plugin findings (#5149)

* make final fields static
* remove unnecessary local before return
* remove instanceof checks in catch clause
* avoid throwing java.lang.Exception
* remove null checks covered by instanceof check
* remove toString on String objects
* remove overrides that only call their super
* remove unused private methods
* remove unnecessary if statement nesting
* remove unused local variables
* use try-with-resources to close resources after use
* use equals() to compare object references
* fix broken javadoc references
* fix disallowed self-closing and empty javadoc elements
* fix bad use of symbols in javadoc
* fix disallowed list item tag in javadoc without surrounding list
* fix erroneous javadoc tags
* fix emphasize tags in javadoc
* remove illegal throws
* remove unused imports

Related:
Terasology/CoreRendering#75
Terasology/Furnishings#17
Terasology/Health#105
Terasology/Inventory#51
Terasology/Behaviors#114
Terasology/CoreWorlds#45
Terasology/FlexiblePathfinding#32

Adds to #3859

engine-tests/src/main/java/org/terasology/engine/Environment.java

@@ -37,16 +37,14 @@ class Environment {
     Environment(Name... moduleNames) {
         try {
             reset(Sets.newHashSet(moduleNames));
+        } catch (RuntimeException e) {
+            throw e;
         } catch (Exception e) {
-            if (e instanceof RuntimeException) {
-                throw (RuntimeException) e;
-            } else {
-                throw new RuntimeException(e);
-            }
+            throw new RuntimeException(e);
         }
     }
 
-    protected void reset(Set<Name> moduleNames) throws Exception {
+    protected void reset(Set<Name> moduleNames) throws IOException {
         this.context = new ContextImpl();
         RecordAndReplayCurrentStatus recordAndReplayCurrentStatus = new RecordAndReplayCurrentStatus();
         context.put(RecordAndReplayCurrentStatus.class, recordAndReplayCurrentStatus);
@@ -99,7 +97,7 @@ protected void setupPathManager() throws IOException {
         PathManager.getInstance();
     }
 
-    protected void setupModuleManager(Set<Name> moduleNames) throws Exception {
+    protected void setupModuleManager(Set<Name> moduleNames) {
         // empty
     }
 
@@ -160,9 +158,9 @@ protected void setupCelestialSystem() {
     /**
      * Cleans up all resources (similar to AutoCloseable)
      *
-     * @throws Exception if something goes wrong
+     * @throws RuntimeException if something goes wrong
      */
-    public void close() throws Exception {
+    public void close() {
         CoreRegistry.setContext(null);
         context = null;
     }

engine-tests/src/main/java/org/terasology/engine/HeadlessEnvironment.java

@@ -263,7 +263,7 @@ protected void setupConfig() {
     }
 
     @Override
-    protected void setupModuleManager(Set<Name> moduleNames) throws Exception {
+    protected void setupModuleManager(Set<Name> moduleNames) throws RuntimeException {
         TypeRegistry.WHITELISTED_CLASSES = ExternalApiWhitelist.CLASSES.stream().map(Class::getName).collect(Collectors.toSet());
 
         ModuleManager moduleManager = ModuleManagerFactory.create();
@@ -320,7 +320,7 @@ protected void loadPrefabs() {
     }
 
     @Override
-    public void close() throws Exception {
+    public void close() throws RuntimeException {
         // it would be nice, if elements in the context implemented (Auto)Closeable
 
         // The StorageManager creates a thread pool (through TaskMaster)

engine-tests/src/main/java/org/terasology/engine/ModuleEnvironmentTest.java

@@ -12,6 +12,7 @@
 import org.terasology.reflection.ModuleTypeRegistry;
 import org.terasology.reflection.TypeRegistry;
 
+import java.io.IOException;
 import java.nio.file.Path;
 import java.util.stream.Collectors;
 
@@ -21,7 +22,7 @@ public abstract class ModuleEnvironmentTest {
     protected ModuleTypeRegistry typeRegistry;
 
     @BeforeEach
-    public void before(@TempDir Path tempHome) throws Exception {
+    public void before(@TempDir Path tempHome) throws IOException {
         PathManager.getInstance().useOverrideHomePath(tempHome);
 
         moduleManager = ModuleManagerFactory.create();

engine-tests/src/main/java/org/terasology/engine/testUtil/ModuleManagerFactory.java

@@ -12,7 +12,7 @@ public final class ModuleManagerFactory {
     private ModuleManagerFactory() {
     }
 
-    public static ModuleManager create() throws Exception {
+    public static ModuleManager create() {
         // Loading screens, among other things, break when NUI classes are not added to engine.
         ModuleManager moduleManager = new ModuleManager("", ImmutableList.of(UIWidget.class));
         Module unittestModule = moduleManager.registerPackageModule("org.terasology.unittest");

engine/src/main/java/org/terasology/engine/audio/formats/OggReader.java

@@ -261,7 +261,7 @@ public long skip(long n) throws IOException {
     /**
      * Initalizes the vorbis stream. Reads the stream until info and comment are read.
      */
-    private void initVorbis() throws Exception {
+    private void initVorbis() throws IOException {
         // Now we can read pages
         syncState.init();
 
@@ -283,7 +283,7 @@ private void initVorbis() throws Exception {
                 return; //break;
             }
             // error case.  Must not be Vorbis data
-            throw new Exception("Input does not appear to be an Ogg bitstream.");
+            throw new IOException("Input does not appear to be an Ogg bitstream.");
         }
 
         // Get the serial number and set up the rest of decode.
@@ -302,15 +302,15 @@ private void initVorbis() throws Exception {
         comment.init();
         if (streamState.pagein(page) < 0) {
             // error; stream version mismatch perhaps
-            throw new Exception("Error reading first page of Ogg bitstream data.");
+            throw new IOException("Error reading first page of Ogg bitstream data.");
         }
         if (streamState.packetout(packet) != 1) {
             // no page? must not be vorbis
-            throw new Exception("Error reading initial header packet.");
+            throw new IOException("Error reading initial header packet.");
         }
         if (info.synthesis_headerin(comment, packet) < 0) {
             // error case; not a vorbis header
-            throw new Exception("This Ogg bitstream does not contain Vorbis audio data.");
+            throw new IOException("This Ogg bitstream does not contain Vorbis audio data.");
         }
 
         // At this point, we're sure we're Vorbis.  We've set up the logical
@@ -346,7 +346,7 @@ private void initVorbis() throws Exception {
                         if (result == -1) {
                             // Uh oh; data at some point was corrupted or missing!
                             // We can't tolerate that in a header.  Die.
-                            throw new Exception("Corrupt secondary header. Exiting.");
+                            throw new IOException("Corrupt secondary header. Exiting.");
                         }
                         info.synthesis_headerin(comment, packet);
                         i++;
@@ -364,7 +364,7 @@ private void initVorbis() throws Exception {
                 bytes = 0;
             }
             if (bytes == 0 && i < 2) {
-                throw new Exception("End of file before finding all Vorbis headers!");
+                throw new IOException("End of file before finding all Vorbis headers!");
             }
             syncState.wrote(bytes);
         }
@@ -386,7 +386,7 @@ private void initVorbis() throws Exception {
      */
     private int decodePacket() {
         // check the endianes of the computer.
-        final boolean bigEndian = ByteOrder.nativeOrder() == ByteOrder.BIG_ENDIAN;
+        final boolean bigEndian = ByteOrder.nativeOrder().equals(ByteOrder.BIG_ENDIAN);
 
         if (block.synthesis(packet) == 0) {
             dspState.synthesis_blockin(block);

engine/src/main/java/org/terasology/engine/audio/openAL/BaseSoundPool.java

@@ -32,10 +32,8 @@ public BaseSoundPool() {
 
     public SOURCE getLockedSource() {
         for (SOURCE source : soundSources.keySet()) {
-            if (!isActive(source)) {
-                if (lock(source)) {
-                    return source;
-                }
+            if (!isActive(source) && lock(source)) {
+                return source;
             }
         }
 

engine/src/main/java/org/terasology/engine/config/flexible/ui/ColorConstraintWidgetFactory.java

@@ -81,7 +81,6 @@ private float findClosestIndex(Color color) {
 
     private Color findClosestColor(float findex) {
         int index = DoubleMath.roundToInt(findex * (double) (colors.size() - 1), RoundingMode.HALF_UP);
-        Color color = colors.get(index);
-        return color;
+        return colors.get(index);
     }
 }

engine/src/main/java/org/terasology/engine/core/GameThread.java

@@ -30,7 +30,7 @@ private GameThread() {
      * @return Whether the currentThread is the gameThread.
      */
     public static boolean isCurrentThread() {
-        return Thread.currentThread() == gameThread;
+        return Thread.currentThread().equals(gameThread);
     }
 
     /**
@@ -41,7 +41,7 @@ public static boolean isCurrentThread() {
      * @param process
      */
     public static void asynch(Runnable process) {
-        if (Thread.currentThread() != gameThread) {
+        if (!Thread.currentThread().equals(gameThread)) {
             pendingRunnables.push(process);
         } else {
             process.run();
@@ -56,7 +56,7 @@ public static void asynch(Runnable process) {
      * @param process
      */
     public static void synch(Runnable process) throws InterruptedException {
-        if (Thread.currentThread() != gameThread) {
+        if (!Thread.currentThread().equals(gameThread)) {
             BlockingProcess blockingProcess = new BlockingProcess(process);
             pendingRunnables.push(blockingProcess);
             blockingProcess.waitForCompletion();
@@ -69,7 +69,7 @@ public static void synch(Runnable process) throws InterruptedException {
      * Runs all pending processes submitted from other threads
      */
     public static void processWaitingProcesses() {
-        if (Thread.currentThread() == gameThread) {
+        if (Thread.currentThread().equals(gameThread)) {
             List<Runnable> processes = Lists.newArrayList();
             pendingRunnables.drainTo(processes);
             processes.forEach(Runnable::run);
@@ -80,7 +80,7 @@ public static void processWaitingProcesses() {
      * Removes all pending processes without running them
      */
     public static void clearWaitingProcesses() {
-        if (gameThread == Thread.currentThread()) {
+        if (gameThread.equals(Thread.currentThread())) {
             pendingRunnables.clear();
         }
     }

engine/src/main/java/org/terasology/engine/core/bootstrap/eventSystem/AbstractEventSystemDecorator.java

@@ -21,7 +21,7 @@ public AbstractEventSystemDecorator(EventSystem eventSystem) {
     }
 
     public boolean currentThreadIsMain() {
-        return mainThread == Thread.currentThread();
+        return mainThread.equals(Thread.currentThread());
     }
 
     @Override

engine/src/main/java/org/terasology/engine/core/modes/StateMainMenu.java

@@ -4,8 +4,6 @@
 
 import com.google.common.base.MoreObjects;
 import org.terasology.engine.audio.AudioManager;
-import org.terasology.engine.config.Config;
-import org.terasology.engine.config.TelemetryConfig;
 import org.terasology.engine.core.GameEngine;
 import org.terasology.engine.core.LoggingContext;
 import org.terasology.engine.core.modes.loadProcesses.RegisterInputSystem;
@@ -17,11 +15,7 @@
 import org.terasology.engine.rendering.nui.NUIManager;
 import org.terasology.engine.rendering.nui.editor.systems.NUIEditorSystem;
 import org.terasology.engine.rendering.nui.editor.systems.NUISkinEditorSystem;
-import org.terasology.engine.rendering.nui.layers.mainMenu.LaunchPopup;
 import org.terasology.engine.rendering.nui.layers.mainMenu.MessagePopup;
-import org.terasology.engine.telemetry.TelemetryScreen;
-import org.terasology.engine.telemetry.TelemetryUtils;
-import org.terasology.engine.telemetry.logstash.TelemetryLogstashAppender;
 import org.terasology.engine.utilities.Assets;
 
 /**
@@ -97,35 +91,6 @@ public void init(GameEngine gameEngine) {
         // pushLaunchPopup();
     }
 
-    private void pushLaunchPopup() {
-        Config config = context.get(Config.class);
-        TelemetryConfig telemetryConfig = config.getTelemetryConfig();
-        TranslationSystem translationSystem = context.get(TranslationSystem.class);
-        TelemetryLogstashAppender appender = TelemetryUtils.fetchTelemetryLogstashAppender();
-        if (!telemetryConfig.isLaunchPopupDisabled()) {
-            String telemetryTitle = translationSystem.translate("${engine:menu#telemetry-launch-popup-title}");
-            String telemetryMessage = translationSystem.translate("${engine:menu#telemetry-launch-popup-text}");
-            LaunchPopup telemetryConfirmPopup = nuiManager.pushScreen(LaunchPopup.ASSET_URI, LaunchPopup.class);
-            telemetryConfirmPopup.setMessage(telemetryTitle, telemetryMessage);
-            telemetryConfirmPopup.setYesHandler(() -> {
-                telemetryConfig.setTelemetryAndErrorReportingEnable(true);
-
-                // Enable error reporting
-                appender.start();
-            });
-            telemetryConfirmPopup.setNoHandler(() -> {
-                telemetryConfig.setTelemetryAndErrorReportingEnable(false);
-
-                // Disable error reporting
-                appender.stop();
-            });
-            telemetryConfirmPopup.setOptionButtonText(translationSystem.translate("${engine:menu#telemetry-button}"));
-            telemetryConfirmPopup.setOptionHandler(() -> {
-                nuiManager.pushScreen(TelemetryScreen.ASSET_URI, TelemetryScreen.class);
-            });
-        }
-    }
-
     @Override
     public void dispose(boolean shuttingDown) {
         stopBackgroundMusic();

engine/src/main/java/org/terasology/engine/core/module/RemoteModuleExtension.java

@@ -9,7 +9,7 @@
 import java.util.Date;
 /**
  * A set of module extensions for remote modules.
- * NOTE: this is copy&paste from meta-server.
+ * NOTE: this is copy&paste from meta-server.
  */
 public enum RemoteModuleExtension {
 

engine/src/main/java/org/terasology/engine/core/subsystem/config/BindsManager.java

@@ -4,7 +4,6 @@
 package org.terasology.engine.core.subsystem.config;
 
 import org.terasology.engine.config.BindsConfig;
-import org.terasology.engine.context.Context;
 import org.terasology.engine.core.SimpleUri;
 import org.terasology.engine.input.BindAxisEvent;
 import org.terasology.engine.input.BindButtonEvent;
@@ -35,14 +34,14 @@
 public interface BindsManager {
 
     /**
-     * The actual binds config. This reflects the current status from {@link #updateDefaultBinds(Context)}
+     * The actual binds config. This reflects the current status from {@link BindsManager#updateConfigWithDefaultBinds()}.
      * and all further modifications like modifications in the user input settings.
      * @return
      */
     BindsConfig getBindsConfig();
 
     /**
-     * The default bindings. This reflects the current status from {@link #updateDefaultBinds(Context)}.
+     * The default bindings. This reflects the current status from {@link BindsManager#updateConfigWithDefaultBinds()}.
      * @return Returns the default bindings. Changes to this config modify the actual instance
      * but become invalid the next time {@link #updateConfigWithDefaultBinds()} is called.
      */

engine/src/main/java/org/terasology/engine/core/subsystem/config/BindsSubsystem.java

@@ -356,7 +356,7 @@ private BindableAxis registerBindAxis(String id, BindAxisEvent event, BindableBu
     }
 
     private BindableAxis registerRealBindAxis(String id, BindAxisEvent event) {
-        BindableRealAxis axis = new BindableRealAxis(id.toString(), event);
+        BindableRealAxis axis = new BindableRealAxis(id, event);
         axisBinds.add(axis);
         axisLookup.put(id, axis);
         return axis;

engine/src/main/java/org/terasology/engine/entitySystem/entity/EntityBuilder.java

@@ -70,10 +70,9 @@ public boolean addPrefab(String prefabName) {
         }
     }
     /**
-     * Adds all of the components from a prefab to this builder
+     * Adds all components from a prefab to this builder
      *
      * @param prefab the prefab to add
-     * @return whether the prefab was successfully added
      */
     public void addPrefab(Prefab prefab) {
         if (prefab != null) {

engine/src/main/java/org/terasology/engine/entitySystem/entity/EntityPool.java

@@ -133,9 +133,9 @@ public interface EntityPool {
      * All entities containing every one of the given components.
      * <p>
      * Implementation note:
-     * <a href="http://www.angelikalanger.com/GenericsFAQ/FAQSections/ProgrammingIdioms.html#Topic5"
-     *     title="Designing Generic Methods">Java generic types are a mess</a>, especially where
-     * varargs are involved. We can't use {@link SafeVarargs @SafeVarargs} on any interface methods
+     * Java generic types are a mess (see <a href="http://www.angelikalanger.com/GenericsFAQ/FAQSections/ProgrammingIdioms.html#Topic5">
+     * Designing Generic Methods</a>), especially where varargs are involved.
+     * We can't use {@link SafeVarargs @SafeVarargs} on any interface methods
      * because there is no way to know the <em>implementations</em> of the interface are safe.
      * <p>
      * In this case, in practice, there are few (if any) callers that pass more than two values.

engine/src/main/java/org/terasology/engine/entitySystem/entity/internal/BaseEntityRef.java

@@ -44,10 +44,8 @@ public boolean isAlwaysRelevant() {
 
     @Override
     public void setAlwaysRelevant(boolean alwaysRelevant) {
-        if (exists()) {
-            if (alwaysRelevant != isAlwaysRelevant()) {
-                setScope(alwaysRelevant ? GLOBAL : CHUNK);
-            }
+        if (exists() && alwaysRelevant != isAlwaysRelevant()) {
+            setScope(alwaysRelevant ? GLOBAL : CHUNK);
         }
     }
 

engine/src/main/java/org/terasology/engine/entitySystem/entity/internal/PojoEntityManager.java

@@ -605,13 +605,9 @@ public void saveComponent(long entityId, Component component) {
 
     public Optional<EngineEntityPool> getPool(long id) {
         Optional<EngineEntityPool> pool = Optional.ofNullable(poolMap.get(id));
-        if (!pool.isPresent()) {
-            if (id != NULL_ID) {
-                // TODO: Entity pools assignment is not needed as of now, can be enabled later on when necessary.
-                if (!isExistingEntity(id)) {
-                    logger.error("Entity {} doesn't exist", id);
-                }
-            }
+        // TODO: Entity pools assignment is not needed as of now, can be enabled later on when necessary.
+        if (!pool.isPresent() && id != NULL_ID && !isExistingEntity(id)) {
+            logger.error("Entity {} doesn't exist", id);
         }
         return pool;
     }
@@ -707,16 +703,6 @@ protected void notifyComponentChanged(EntityRef changedEntity, Class<? extends C
         }
     }
 
-    /**
-     * This method gets called when the entity gets reactivated. e.g. after storage an entity needs to be reactivated.
-     */
-    private void notifyReactivation(EntityRef entity, Collection<Component> components) {
-        for (EntityChangeSubscriber subscriber : subscribers) {
-            subscriber.onReactivation(entity, components);
-        }
-    }
-
-
     /**
      * This method gets called before an entity gets deactivated (e.g. for storage).
      */