fix apache#6742 cache Class avoid PermGen space OOM

xiaoheng1 · Mar 16, 2021 · e585346 · e585346
1 parent d009d0c
commit e585346
Showing 1 changed file with 33 additions and 7 deletions.
diff --git a/dubbo-common/src/main/java/org/apache/dubbo/common/bytecode/Proxy.java b/dubbo-common/src/main/java/org/apache/dubbo/common/bytecode/Proxy.java
@@ -50,6 +50,8 @@ public Object invoke(Object proxy, Method method, Object[] args) {
     private static final AtomicLong PROXY_CLASS_COUNTER = new AtomicLong(0);
     private static final String PACKAGE_NAME = Proxy.class.getPackage().getName();
     private static final Map<ClassLoader, Map<String, Object>> PROXY_CACHE_MAP = new WeakHashMap<ClassLoader, Map<String, Object>>();
+    // cache class, avoid PermGen OOM.
+    private static final Map<ClassLoader, Map<String, Class<?>>> PROXY_CLASS_MAP = new WeakHashMap<ClassLoader, Map<String, Class<?>>>();
 
     private static final Object PENDING_GENERATION_MARKER = new Object();
 
@@ -103,8 +105,11 @@ public static Proxy getProxy(ClassLoader cl, Class<?>... ics) {
 
         // get cache by class loader.
         final Map<String, Object> cache;
+        // cache class
+        final Map<String, Class<?>> classCache;
         synchronized (PROXY_CACHE_MAP) {
             cache = PROXY_CACHE_MAP.computeIfAbsent(cl, k -> new HashMap<>());
+            classCache = PROXY_CLASS_MAP.computeIfAbsent(cl, k -> new HashMap<>());
         }
 
         Proxy proxy = null;
@@ -118,14 +123,31 @@ public static Proxy getProxy(ClassLoader cl, Class<?>... ics) {
                     }
                 }
 
-                if (value == PENDING_GENERATION_MARKER) {
-                    try {
-                        cache.wait();
-                    } catch (InterruptedException e) {
+                // get Class by key.
+                Class<?> clazz = classCache.get(key);
+                if (null == clazz) {
+                    if (value == PENDING_GENERATION_MARKER) {
+                        try {
+                            cache.wait();
+                        } catch (InterruptedException e) {
+                        }
+                    } else {
+                        cache.put(key, PENDING_GENERATION_MARKER);
+                        break;
                     }
                 } else {
-                    cache.put(key, PENDING_GENERATION_MARKER);
-                    break;
+                    try {
+                        proxy = (Proxy) clazz.newInstance();
+                        return proxy;
+                    } catch (InstantiationException | IllegalAccessException e) {
+                        throw new RuntimeException(e);
+                    } finally {
+                        if (null == proxy) {
+                            cache.remove(key);
+                        } else {
+                            cache.put(key, new WeakReference<Proxy>(proxy));
+                        }
+                    }
                 }
             }
             while (true);
@@ -187,7 +209,7 @@ public static Proxy getProxy(ClassLoader cl, Class<?>... ics) {
             ccp.setClassName(pcn);
             ccp.addField("public static java.lang.reflect.Method[] methods;");
             ccp.addField("private " + InvocationHandler.class.getName() + " handler;");
-            ccp.addConstructor(Modifier.PUBLIC, new Class<?>[]{InvocationHandler.class}, new Class<?>[0], "handler=$1;");
+            ccp.addConstructor(Modifier.PUBLIC, new Class<?>[] {InvocationHandler.class}, new Class<?>[0], "handler=$1;");
             ccp.addDefaultConstructor();
             Class<?> clazz = ccp.toClass();
             clazz.getField("methods").set(null, methods.toArray(new Method[0]));
@@ -201,6 +223,10 @@ public static Proxy getProxy(ClassLoader cl, Class<?>... ics) {
             ccm.addMethod("public Object newInstance(" + InvocationHandler.class.getName() + " h){ return new " + pcn + "($1); }");
             Class<?> pc = ccm.toClass();
             proxy = (Proxy) pc.newInstance();
+
+            synchronized (classCache) {
+                classCache.put(key, pc);
+            }
         } catch (RuntimeException e) {
             throw e;
         } catch (Exception e) {