fix: the executor service now uses SynchronousQueue

The current approach used a non-bound queue, therefore the thread were not added dynamically into the Threadpool

Signed-off-by: Attila Mészáros <csviri@gmail.com>

Author: csviri

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/ExecutorServiceManager.java

@@ -3,15 +3,7 @@
 import java.time.Duration;
 import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.Callable;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.Future;
-import java.util.concurrent.LinkedBlockingDeque;
-import java.util.concurrent.ThreadPoolExecutor;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.TimeoutException;
+import java.util.concurrent.*;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -37,9 +29,8 @@ public class ExecutorServiceManager {
   public static ExecutorService newThreadPoolExecutor(int minThreads, int maxThreads) {
     minThreads = Utils.ensureValid(minThreads, "minimum number of threads", MIN_THREAD_NUMBER);
     maxThreads = Utils.ensureValid(maxThreads, "maximum number of threads", minThreads + 1);
-
     return new ThreadPoolExecutor(minThreads, maxThreads, 1, TimeUnit.MINUTES,
-        new LinkedBlockingDeque<>());
+        new SynchronousQueue<>());
   }
 
   /**