POLYGENE-308 - Finally found the evasive concurrency bug. AtomicInstancePool was not thread-safe after all, and is replaced by using the ConcurrentLinkedQueue in standard library instead. No idea why this was not used in the first place, possibly to add "removal" feature in the future.

Author: niclash

core/runtime/src/main/java/org/apache/polygene/runtime/composite/AtomicInstancePool.java

@@ -29,6 +29,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.apache.polygene.api.common.ConstructionException;
@@ -56,7 +57,7 @@ public final class CompositeMethodModel
 
     // Context
 //    private final SynchronizedCompositeMethodInstancePool instancePool = new SynchronizedCompositeMethodInstancePool();
-    private final AtomicInstancePool instancePool = new AtomicInstancePool();
+    private final ConcurrentLinkedQueue<CompositeMethodInstance> instancePool = new ConcurrentLinkedQueue<>();
     private final ConstraintsInstance constraintsInstance;
 
     public CompositeMethodModel( Method method,
@@ -111,13 +112,13 @@ public Object invoke( Object composite, Object[] params, MixinsInstance mixins,
         }
         finally
         {
-            instancePool.releaseInstance( methodInstance );
+            instancePool.offer( methodInstance );
         }
     }
 
     private CompositeMethodInstance getInstance( ModuleDescriptor module )
     {
-        CompositeMethodInstance methodInstance = instancePool.obtainInstance();
+        CompositeMethodInstance methodInstance = instancePool.poll();
         if( methodInstance == null )
         {
             methodInstance = newCompositeMethodInstance( module );

core/runtime/src/main/java/org/apache/polygene/runtime/composite/CompositeMethodModel.java

@@ -1,3 +1,20 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
 package org.apache.polygene.runtime.composite;
 
 import org.apache.polygene.api.injection.scope.Service;
@@ -6,21 +23,20 @@
 import org.apache.polygene.bootstrap.AssemblyException;
 import org.apache.polygene.bootstrap.ModuleAssembly;
 import org.apache.polygene.test.AbstractPolygeneTest;
+import org.junit.jupiter.api.RepeatedTest;
 import org.junit.jupiter.api.Test;
 
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 
+/** Regression test POLYGENE-308
+ */
 public class CompositeMethodInvocationTest extends AbstractPolygeneTest {
 
     @Service
     MyService srv;
 
-    /**
-     * To correct, change instance pool type in CompositeMethodModel
-     * AtomicInstancePool -> SynchronizedCompositeMethodInstancePool
-     */
     @Test
     public void corruptedMethodInvocation() throws InterruptedException {
         srv.dummy(); // to avoid concurrent activation (it can have own issues)
@@ -33,7 +49,7 @@ public void corruptedMethodInvocation() throws InterruptedException {
                 }
             });
         }
-        exe.awaitTermination(10, TimeUnit.MINUTES);
+        exe.awaitTermination(30, TimeUnit.SECONDS);
     }
 
     @Override