1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/test/runtime/jni/ReturnJNIWeak/ReturnJNIWeak.java Fri May 10 18:50:40 2019 +0000
1.3 @@ -0,0 +1,122 @@
1.4 +/*
1.5 + * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + */
1.26 +
1.27 +public final class ReturnJNIWeak {
1.28 + static {
1.29 + System.loadLibrary("ReturnJNIWeak");
1.30 + }
1.31 +
1.32 + private static final class TestObject {
1.33 + public final int value;
1.34 +
1.35 + public TestObject(int value) {
1.36 + this.value = value;
1.37 + }
1.38 + }
1.39 +
1.40 + private static volatile TestObject testObject = null;
1.41 +
1.42 + private static native void registerObject(Object o);
1.43 + private static native void unregisterObject();
1.44 + private static native Object getObject();
1.45 +
1.46 + // Create the test object and record it both strongly and weakly.
1.47 + private static void remember(int value) {
1.48 + TestObject o = new TestObject(value);
1.49 + registerObject(o);
1.50 + testObject = o;
1.51 + }
1.52 +
1.53 + // Remove both strong and weak references to the current test object.
1.54 + private static void forget() {
1.55 + unregisterObject();
1.56 + testObject = null;
1.57 + }
1.58 +
1.59 + // Verify the weakly recorded object
1.60 + private static void checkValue(int value) throws Exception {
1.61 + Object o = getObject();
1.62 + if (o == null) {
1.63 + throw new RuntimeException("Weak reference unexpectedly null");
1.64 + }
1.65 + TestObject t = (TestObject)o;
1.66 + if (t.value != value) {
1.67 + throw new RuntimeException("Incorrect value");
1.68 + }
1.69 + }
1.70 +
1.71 + // Verify we can create a weak reference and get it back.
1.72 + private static void testSanity() throws Exception {
1.73 + System.out.println("running testSanity");
1.74 + int value = 5;
1.75 + try {
1.76 + remember(value);
1.77 + checkValue(value);
1.78 + } finally {
1.79 + forget();
1.80 + }
1.81 + }
1.82 +
1.83 + // Verify weak ref value survives across collection if strong ref exists.
1.84 + private static void testSurvival() throws Exception {
1.85 + System.out.println("running testSurvival");
1.86 + int value = 10;
1.87 + try {
1.88 + remember(value);
1.89 + checkValue(value);
1.90 + System.gc();
1.91 + // Verify weak ref still has expected value.
1.92 + checkValue(value);
1.93 + } finally {
1.94 + forget();
1.95 + }
1.96 + }
1.97 +
1.98 + // Verify weak ref cleared if no strong ref exists.
1.99 + private static void testClear() throws Exception {
1.100 + System.out.println("running testClear");
1.101 + int value = 15;
1.102 + try {
1.103 + remember(value);
1.104 + checkValue(value);
1.105 + // Verify still good.
1.106 + checkValue(value);
1.107 + // Drop reference.
1.108 + testObject = null;
1.109 + System.gc();
1.110 + // Verify weak ref cleared as expected.
1.111 + Object recorded = getObject();
1.112 + if (recorded != null) {
1.113 + throw new RuntimeException("expected clear");
1.114 + }
1.115 + } finally {
1.116 + forget();
1.117 + }
1.118 + }
1.119 +
1.120 + public static void main(String[] args) throws Exception {
1.121 + testSanity();
1.122 + testSurvival();
1.123 + testClear();
1.124 + }
1.125 +}
