8210788: Javadoc for Thread.join(long, int) should specify that it waits...

8210788: Javadoc for Thread.join(long, int) should specify that it waits forever when both arguments are zero
Reviewed-by: martin, rriggs

src/java.base/share/classes/java/lang/Thread.java

 /*
- * Copyright (c) 1994, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1319,6 +1319,7 @@ class Thread implements Runnable {
     /**
      * Waits at most {@code millis} milliseconds plus
      * {@code nanos} nanoseconds for this thread to die.
+     * If both arguments are {@code 0}, it means to wait forever.
      *
      * <p> This implementation uses a loop of {@code this.wait} calls
      * conditioned on {@code this.isAlive}. As a thread terminates the