Add Override annotations where appropriate

By: md_5 <git@md-5.net>

paper-server/src/main/java/org/bukkit/craftbukkit/scheduler/CraftAsyncTask.java

@@ -33,14 +33,17 @@ class CraftAsyncTask extends CraftTask {
             }
             workers.add(
                 new BukkitWorker() {
+                    @Override
                     public Thread getThread() {
                         return thread;
                     }
 
+                    @Override
                     public int getTaskId() {
                         return CraftAsyncTask.this.getTaskId();
                     }
 
+                    @Override
                     public Plugin getOwner() {
                         return CraftAsyncTask.this.getOwner();
                     }
@@ -95,6 +98,7 @@ class CraftAsyncTask extends CraftTask {
         return workers;
     }
 
+    @Override
     boolean cancel0() {
         synchronized (workers) {
             // Synchronizing here prevents race condition for a completing task

paper-server/src/main/java/org/bukkit/craftbukkit/scheduler/CraftFuture.java

@@ -19,6 +19,7 @@ class CraftFuture<T> extends CraftTask implements Future<T> {
         this.callable = callable;
     }
 
+    @Override
     public synchronized boolean cancel(final boolean mayInterruptIfRunning) {
         if (getPeriod() != CraftTask.NO_REPEATING) {
             return false;
@@ -27,11 +28,13 @@ class CraftFuture<T> extends CraftTask implements Future<T> {
         return true;
     }
 
+    @Override
     public boolean isDone() {
         final long period = this.getPeriod();
         return period != CraftTask.NO_REPEATING && period != CraftTask.PROCESS_FOR_FUTURE;
     }
 
+    @Override
     public T get() throws CancellationException, InterruptedException, ExecutionException {
         try {
             return get(0, TimeUnit.MILLISECONDS);
@@ -40,6 +43,7 @@ class CraftFuture<T> extends CraftTask implements Future<T> {
         }
     }
 
+    @Override
     public synchronized T get(long timeout, final TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
         timeout = unit.toMillis(timeout);
         long period = this.getPeriod();
@@ -92,6 +96,7 @@ class CraftFuture<T> extends CraftTask implements Future<T> {
         }
     }
 
+    @Override
     synchronized boolean cancel0() {
         if (getPeriod() != CraftTask.NO_REPEATING) {
             return false;

paper-server/src/main/java/org/bukkit/craftbukkit/scheduler/CraftScheduler.java

@@ -60,6 +60,7 @@ public class CraftScheduler implements BukkitScheduler {
      */
     private final PriorityQueue<CraftTask> pending = new PriorityQueue<CraftTask>(10,
             new Comparator<CraftTask>() {
+                @Override
                 public int compare(final CraftTask o1, final CraftTask o2) {
                     int value = Long.compare(o1.getNextRun(), o2.getNextRun());
 
@@ -227,6 +228,7 @@ public class CraftScheduler implements BukkitScheduler {
         }
         task = new CraftTask(
                 new Runnable() {
+                    @Override
                     public void run() {
                         if (!check(CraftScheduler.this.temp)) {
                             check(CraftScheduler.this.pending);
@@ -263,6 +265,7 @@ public class CraftScheduler implements BukkitScheduler {
         Validate.notNull(plugin, "Cannot cancel tasks of null plugin");
         final CraftTask task = new CraftTask(
                 new Runnable() {
+                    @Override
                     public void run() {
                         check(CraftScheduler.this.pending);
                         check(CraftScheduler.this.temp);