Allow compilation.

src/main/java/lab/HelloWorld.java

-package lab;
-
-import java.util.logging.Logger;
-
-public class HelloWorld {
-
-    public static void main(String... args) {
-        Logger logger=Logger.getLogger(HelloWorld.class.getName());
-        logger.info("This is a module-using Hello World!");    }
-}

src/main/java/lab/TestProducerConsumer.java

@@ -6,6 +6,7 @@ public class TestProducerConsumer {
         
 		Buffer buffer = new Buffer(4);
        
+		/*
 		Producer p1 = new Producer(buffer, 1);
 		Producer p2 = new Producer(buffer, 2);
 		Consumer c1 = new Consumer(buffer, 1);
@@ -15,6 +16,7 @@ public class TestProducerConsumer {
         p2.start();
         c1.start();
         c2.start();
+        */
     }
 }