1 /*
   2  * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2019 SAP SE. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  */
  24 
  25 /**
  26  * @test
  27  * @summary Test NullPointerException messages thrown in frames that
  28  *   are hidden in the backtrace/stackTrace.
  29  * @library /test/lib
  30  * @compile -g NPEInHiddenTopFrameTest.java
  31  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:-ShowHiddenFrames -XX:-ShowCodeDetailsInExceptionMessages NPEInHiddenTopFrameTest hidden
  32  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+ShowHiddenFrames -XX:+ShowCodeDetailsInExceptionMessages NPEInHiddenTopFrameTest visible
  33  */
  34 
  35 import jdk.test.lib.Asserts;
  36 
  37 public class NPEInHiddenTopFrameTest {
  38 
  39     @FunctionalInterface
  40     private static interface SomeFunctionalInterface {
  41         String someMethod(String a, String b);
  42     }
  43 
  44     public static void checkMessage(String expression,
  45                                     String obtainedMsg, String expectedMsg) {
  46         System.out.println();
  47         System.out.println(" source code: " + expression);
  48         System.out.println("  thrown msg: " + obtainedMsg);
  49         if (obtainedMsg == null && expectedMsg == null) return;
  50         System.out.println("expected msg: " + expectedMsg);
  51         Asserts.assertEquals(expectedMsg, obtainedMsg);
  52     }
  53 
  54     public static void main(String[] args) throws Exception {
  55         boolean framesAreHidden = false;
  56         if (args.length > 0) {
  57             String arg = args[0];
  58             if (arg.equals("hidden")) framesAreHidden = true;
  59         }
  60 
  61         try {
  62             final SomeFunctionalInterface concatter = String::concat;
  63             final String nullString = null;
  64             if (concatter != null) {
  65                 // This throws NPE from the lambda expression which is a hidden frame.
  66                 concatter.someMethod(nullString, "validString");
  67             }
  68         } catch (NullPointerException e) {
  69             checkMessage("concatter.someMethod(nullString, \"validString\");", e.getMessage(),
  70                          framesAreHidden ?
  71                          // This is the message printed if the wrong method/bci are used:
  72                          // "Cannot invoke 'NPEInHiddenTopFrameTest$SomeFunctionalInterface.someMethod(String, String)'" +
  73                          // " because 'concatter' is null."
  74                          // With this fix no message is printed.
  75                          null :
  76                          // This is the correct message, but it describes code generated on-the-fly.
  77                          // You get it if you disable hiding frames (-XX:+ShowHiddenframes).
  78                          "Cannot invoke 'String.concat(String)' because '<parameter1>' is null." );
  79             e.printStackTrace();
  80         }
  81     }
  82 }
  83