8231454: File lock in Windows on a loaded jar due to a leak in Introspector::getBeanInfo

Reviewed-by: kizune

src/java.desktop/share/classes/com/sun/beans/introspect/ClassInfo.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -22,14 +22,15 @@
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
-package com.sun.beans.introspect;
 
-import com.sun.beans.util.Cache;
+package com.sun.beans.introspect;
 
 import java.lang.reflect.Method;
 import java.util.List;
 import java.util.Map;
 
+import com.sun.beans.util.Cache;
+
 import static sun.reflect.misc.ReflectUtil.checkPackageAccess;
 
 public final class ClassInfo {
@@ -54,6 +55,14 @@ public final class ClassInfo {
         }
     }
 
+    public static void clear() {
+        CACHE.clear();
+    }
+
+    public static void remove(Class<?> clz) {
+        CACHE.remove(clz);
+    }
+
     private final Object mutex = new Object();
     private final Class<?> type;
     private List<Method> methods;

src/java.desktop/share/classes/java/beans/Introspector.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1996, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -364,6 +364,7 @@ public class Introspector {
      */
     public static void flushCaches() {
         ThreadGroupContext.getContext().clearBeanInfoCache();
+        ClassInfo.clear();
     }
 
     /**
@@ -387,6 +388,7 @@ public class Introspector {
             throw new NullPointerException();
         }
         ThreadGroupContext.getContext().removeBeanInfo(clz);
+        ClassInfo.remove(clz);
     }
 
     //======================================================================

test/jdk/java/beans/Introspector/FlushClassInfoCache.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * 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.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.beans.IntrospectionException;
+import java.beans.Introspector;
+import java.lang.ref.Reference;
+import java.lang.ref.WeakReference;
+import java.net.URL;
+import java.net.URLClassLoader;
+
+/**
+ * @test
+ * @bug 8231454
+ * @summary Tests cache cleanup by the Introspector.flushXXX()
+ */
+public final class FlushClassInfoCache {
+
+    public static void main(String[] args) throws Exception {
+        verify(getLoader("testClass"));
+        verify(getLoader("testAll"));
+        Reference<ClassLoader> loader = getLoader("test");
+        // Clear the cache in com.sun.beans.introspect.ClassInfo::CACHE
+        Introspector.flushCaches();
+        verify(loader);
+    }
+
+    private static void verify(Reference<?> loader) throws Exception {
+        int attempt = 0;
+        while (loader.get() != null) {
+            if (++attempt > 10) {
+                throw new RuntimeException("Too many attempts: " + attempt);
+            }
+            // Cannot generate OOM here, it will clear the CACHE as well
+            System.gc();
+            Thread.sleep(1000);
+            System.out.println("Not freed :(");
+        }
+    }
+
+    public static void test() {
+        try {
+            Introspector.getBeanInfo(FlushClassInfoCache.class);
+        } catch (IntrospectionException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static void testClass() {
+        try {
+            Introspector.getBeanInfo(FlushClassInfoCache.class);
+            // Clear the cache in com.sun.beans.introspect.ClassInfo::CACHE
+            Introspector.flushFromCaches(FlushClassInfoCache.class);
+        } catch (IntrospectionException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static void testAll() {
+        try {
+            Introspector.getBeanInfo(FlushClassInfoCache.class);
+            // Clear the cache in com.sun.beans.introspect.ClassInfo::CACHE
+            Introspector.flushCaches();
+        } catch (IntrospectionException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private static Reference<ClassLoader> getLoader(String m) throws Exception {
+        URL url = FlushClassInfoCache.class.getProtectionDomain()
+                                     .getCodeSource().getLocation();
+        URLClassLoader loader = new URLClassLoader(new URL[]{url}, null);
+        Class<?> cls = Class.forName("FlushClassInfoCache", true, loader);
+        cls.getDeclaredMethod(m).invoke(null);
+        loader.close();
+        return new WeakReference<>(loader);
+    }
+}