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1 /* |
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2 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 */ |
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23 |
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24 /* |
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25 * @test KeepAliveObject |
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26 * @summary This test case uses a class instance to keep the class alive. |
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27 * @library /testlibrary /testlibrary/whitebox /runtime/testlibrary |
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28 * @library classes |
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29 * @build KeepAliveObject test.Empty |
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30 * @build ClassUnloadCommon |
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31 * @run main ClassFileInstaller sun.hotspot.WhiteBox |
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32 * @run main/othervm -Xbootclasspath/a:. -Xmn8m -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI KeepAliveObject |
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33 */ |
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34 |
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35 import sun.hotspot.WhiteBox; |
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36 |
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37 /** |
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38 * Test that verifies that classes are not unloaded when specific types of references are kept to them. |
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39 */ |
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40 public class KeepAliveObject { |
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41 private static final String className = "test.Empty"; |
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42 private static final WhiteBox wb = WhiteBox.getWhiteBox(); |
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43 public static Object escape = null; |
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44 |
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45 public static void main(String... args) throws Exception { |
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46 ClassLoader cl = ClassUnloadCommon.newClassLoader(); |
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47 Class<?> c = cl.loadClass(className); |
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48 Object o = c.newInstance(); |
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49 cl = null; c = null; |
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50 escape = o; |
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51 |
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52 { |
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53 boolean isAlive = wb.isClassAlive(className); |
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54 System.out.println("testObject (1) alive: " + isAlive); |
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55 |
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56 ClassUnloadCommon.failIf(!isAlive, "should be alive"); |
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57 } |
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58 |
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59 ClassUnloadCommon.triggerUnloading(); |
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60 |
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61 { |
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62 boolean isAlive = wb.isClassAlive(className); |
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63 System.out.println("testObject (2) alive: " + isAlive); |
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64 |
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65 ClassUnloadCommon.failIf(!isAlive, "should be alive"); |
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66 } |
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67 o = null; |
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68 escape = null; |
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69 ClassUnloadCommon.triggerUnloading(); |
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70 |
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71 { |
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72 boolean isAlive = wb.isClassAlive(className); |
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73 System.out.println("testObject (3) alive: " + isAlive); |
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74 ClassUnloadCommon.failIf(isAlive, "should be unloaded"); |
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75 } |
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76 |
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77 } |
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78 } |