Merge pull request #7927 from IgorNB/patch-1

SemaPhoreDemo double acquire fix

core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/semaphore/SemaPhoreDemo.java

@@ -12,10 +12,12 @@ public class SemaPhoreDemo {
 		System.out.println("Number of threads waiting to acquire: " + semaphore.getQueueLength());
 
 		if (semaphore.tryAcquire()) {
-			semaphore.acquire();
+			try {		
 			// perform some critical operations
+			} finally {
 				semaphore.release();
 			}
+		}
 
 	}