Integrate r10431 into GWT 2.4 branch.

Review by: rjrjr@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/releases/2.4@10583 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/user/test/com/google/web/bindery/requestfactory/apt/RfValidatorTest.java b/user/test/com/google/web/bindery/requestfactory/apt/RfValidatorTest.java
index 55cbd59..a6c3ec7 100644
--- a/user/test/com/google/web/bindery/requestfactory/apt/RfValidatorTest.java
+++ b/user/test/com/google/web/bindery/requestfactory/apt/RfValidatorTest.java
@@ -154,6 +154,10 @@
    */
   private void testGeneratedMessages(boolean clientOnly, Class<?>... classes) throws IOException {
     JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
+    if (compiler == null) {
+      // This test is being run without a full JDK
+      return;
+    }
 
     // Don't spray files in random locations
     File tempFile = File.createTempFile(RfValidatorTest.class.getSimpleName(), ".jar");