Update App.java

tinochan · tinochan · commit d2aa34756785 · 2015-11-21T12:09:41.000+08:00
Added comment.
diff --git a/JavaMultiThreadingCodes/src/VolatileKeyword_2/App.java b/JavaMultiThreadingCodes/src/VolatileKeyword_2/App.java
@@ -15,6 +15,13 @@
  * </a>
  *
  * @author Z.B. Celik <celik.berkay@gmail.com>
+ * 
+ * Normally, the below program will stop running after you
+ * press return. But in some system it won't. As after
+ * Java optimize the code, one thread doesn't expect other
+ * thread to modify its fields, that is the value of
+ * running. So to guarantee it works on all system or OS,
+ * we use volatile. It prevents cache caching the variables.
  */
 import java.util.Scanner;
 
