--- old/test/tools/javac/processing/model/TestSourceVersion.java	2016-05-18 11:11:48.503519161 -0700
+++ new/test/tools/javac/processing/model/TestSourceVersion.java	2016-05-18 11:11:48.419477163 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2016, 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
@@ -23,13 +23,14 @@
 
 /*
  * @test
- * @bug 7025809 8028543
- * @summary Test latest and latestSupported
+ * @bug 7025809 8028543 6415644
+ * @summary Test latest, latestSupported, underscore as keyword, etc.
  * @author  Joseph D. Darcy
  * @modules java.compiler
  *          jdk.compiler
  */
 
+import java.util.*;
 import javax.lang.model.SourceVersion;
 import static javax.lang.model.SourceVersion.*;
 
@@ -38,10 +39,45 @@
  */
 public class TestSourceVersion {
     public static void main(String... args) {
+        testLatestSupported();
+        testVersionVaryingKeywords();
+    }
+
+    private static void testLatestSupported() {
         if (SourceVersion.latest() != RELEASE_9 ||
             SourceVersion.latestSupported() != RELEASE_9)
             throw new RuntimeException("Unexpected release value(s) found:\n" +
                                        "latest:\t" + SourceVersion.latest() + "\n" +
                                        "latestSupported:\t" + SourceVersion.latestSupported());
     }
+
+    private static void testVersionVaryingKeywords() {
+        Map<String, SourceVersion> keyWordStart = 
+            Map.of("strictfp", RELEASE_2,
+                   "assert",   RELEASE_4,
+                   "enum",     RELEASE_5,
+                   "_",        RELEASE_9);
+
+        for (Map.Entry<String, SourceVersion> entry : keyWordStart.entrySet()) {
+            String key = entry.getKey();
+            SourceVersion value = entry.getValue();
+
+            check(true, isKeyword(key), "keyword", latest());
+            check(false, isName(key),   "name",    latest());
+
+            for(SourceVersion version : SourceVersion.values()) {
+                boolean isKeyword = version.compareTo(value) >= 0;
+
+                check(isKeyword,  isKeyword(key, version), "keyword", version);
+                check(!isKeyword, isName(key, version),    "name",    version);
+            }
+        }
+    }
+
+    private static void check(boolean result, boolean expected,
+                              String message, SourceVersion version) {
+        if (result != expected) {
+            throw new RuntimeException("Unexpected " + message +  "-ness of _ on " + version);
+        }
+    }
 }