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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 *
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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/**
 * @test
 * @summary Test NullPointerException messages thrown in frames that
 *   are hidden in the backtrace/stackTrace.
 * @bug 8218628
 * @library /test/lib
 * @compile -g NPEInHiddenTopFrameTest.java
 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:-ShowHiddenFrames -XX:+ShowCodeDetailsInExceptionMessages NPEInHiddenTopFrameTest hidden
 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+ShowHiddenFrames -XX:+ShowCodeDetailsInExceptionMessages NPEInHiddenTopFrameTest visible
 */

import jdk.test.lib.Asserts;

public class NPEInHiddenTopFrameTest {

    @FunctionalInterface
    private static interface SomeFunctionalInterface {
        String someMethod(String a, String b);
    }

    public static void checkMessage(String expression,
                                    String obtainedMsg, String expectedMsg) {
        System.out.println();
        System.out.println(" source code: " + expression);
        System.out.println("  thrown msg: " + obtainedMsg);
        if (obtainedMsg == null && expectedMsg == null) return;
        System.out.println("expected msg: " + expectedMsg);
        Asserts.assertEquals(expectedMsg, obtainedMsg);
    }

    public static void main(String[] args) throws Exception {
        boolean framesAreHidden = false;
        if (args.length > 0) {
            String arg = args[0];
            if (arg.equals("hidden")) framesAreHidden = true;
        }

        try {
            final SomeFunctionalInterface concatter = String::concat;
            final String nullString = null;
            if (concatter != null) {
                // This throws NPE from the lambda expression which is a hidden frame.
                concatter.someMethod(nullString, "validString");
            }
        } catch (NullPointerException e) {
            checkMessage("concatter.someMethod(nullString, \"validString\");", e.getMessage(),
                         framesAreHidden ?
                         // This is the message that would be printed if the wrong method/bci are used:
                         // "Cannot invoke 'NPEInHiddenTopFrameTest$SomeFunctionalInterface.someMethod(String, String)'" +
                         // " because 'concatter' is null."
                         // But the NPE message generation now recognizes this situation and skips the 
                         // message. So we expect null:
                         null :
                         // This is the correct message, but it describes code generated on-the-fly.
                         // You get it if you disable hiding frames (-XX:+ShowHiddenframes).
                         "Cannot invoke 'String.concat(String)' because '<parameter1>' is null." );
            e.printStackTrace();
        }
    }
}