Fix Bugs listed by Sonar Qube.

Author: tk

cuckoo-uci/src/main/java/org/petero/cuckoo/uci/EngineControl.java

@@ -159,6 +159,9 @@ public final void ponderHit() {
 		}
 		infinite = (maxTimeLimit < 0) && (maxDepth < 0) && (maxNodes < 0);
 		ponder = false;
+		synchronized (threadMutex) {
+			threadMutex.notifyAll();
+		}
 	}
 
 	public final void stopSearch() {
@@ -239,7 +242,7 @@ private void startThread(final int minTimeLimit, final int maxTimeLimit, int max
 		}
 		tt.nextGeneration();
 		final int srchmaxDepth = maxDepth;
-		engineThread = Thread.ofVirtual().start(() -> {
+		engineThread = new Thread(() -> {
 			Move m = null;
 			if (ownBook && !analyseMode) {
 				Book book = new Book(false);
@@ -248,14 +251,17 @@ private void startThread(final int minTimeLimit, final int maxTimeLimit, int max
 			if (m == null) {
 				m = sc.iterativeDeepening(srchMoves, srchmaxDepth, maxNodes, false);
 			}
-			while (ponder || infinite) {
+
 				// We should not respond until told to do so. Just wait
 				// until
 				// we are allowed to respond.
-				try {
-					Thread.sleep(10);
-				} catch (InterruptedException ex) {
-					break;
+			synchronized (threadMutex) {
+				while (ponder || infinite) {
+					try {
+						threadMutex.wait();
+					} catch (InterruptedException ex) {
+						Thread.currentThread().interrupt();
+					}
 				}
 			}
 			Move ponderMove = getPonderMove(pos, m);