add finally block

u05-4/WorkQueue.java

@@ -45,10 +45,11 @@ class WorkQueue {
 		} catch (NoSuchElementException e) {
 			System.out.println("!!! No taks in queue (BUT STILL TRIED ACCESSING)");
 			return;
+		} finally {
+			generalAccessSemaphore.release();
 		}
 
 		writeSemaphore.release();
-		generalAccessSemaphore.release();
 
 		t.run();
 	}