LRUCachePolicy incompatiblity WAS Re: [jboss-dev] Remoting shutdown errors and warnings

[Dimitris Andreadis]

Great catch.

So it's this change that crept in jboss-common-core 2.2.8.GA by Ales, without even a linked 
JIRA issue:

To be honest, I wouldn't have thought that changing a protected field to a supertype would 
present compatibility issues.

I've made a jira for Ron, since we are expecting a remoting 2.2.4.SP2, anyway:
https://jira.jboss.org/jira/browse/JBREM-1032

Or the other option would be to rollback Ales' change, but then something else will break.

Index: X:/cvs/jboss-public/common/common-core/src/main/java/org/jboss/util/LRUCachePolicy.java
===================================================================
--- X:/cvs/jboss-public/common/common-core/src/main/java/org/jboss/util/LRUCachePolicy.java 
(revision 2882)
+++ X:/cvs/jboss-public/common/common-core/src/main/java/org/jboss/util/LRUCachePolicy.java 
(revision 2883)
@@ -22,6 +22,7 @@
  package org.jboss.util;

  import java.util.HashMap;
+import java.util.Map;

  /**
   * Implementation of a Least Recently Used cache policy.
@@ -39,7 +40,7 @@
     /**
      * The map holding the cached objects
      */
-   protected HashMap m_map;
+   protected Map m_map;
     /**
      * The linked list used to implement the LRU algorithm
      */
@@ -79,6 +80,16 @@
        m_maxCapacity = max;
     }

+   /**
+    * Create map holding entries.
+    *
+    * @return the map
+    */
+   protected Map createMap()
+   {
+      return new HashMap();
+   }
+
     // Public --------------------------------------------------------

     // Service implementation ----------------------------------------------
@@ -90,7 +101,7 @@
      */
     public void create()
     {
-      m_map = new HashMap();
+      m_map = createMap();
        m_list = createList();
        m_list.m_maxCapacity = m_maxCapacity;
        m_list.m_minCapacity = m_minCapacity;


Adrian Brock wrote:
> On Thu, 2008-09-04 at 16:28 +0200, Carlo de Wolf wrote:
>> On Thu, 2008-09-04 at 15:39 +0200, Adrian Brock wrote:
>>> 15:15:34,302 WARN  [StartStopLifecycleAction] Error during stop for
>>> org.jboss.ejb3.RemotingConnector
>>> java.lang.NoSuchFieldError: m_map
>>>         at org.jboss.remoting.transport.socket.LRUPool.getContents(LRUPool.java:81)
>>>         at org.jboss.remoting.transport.socket.SocketServerInvoker.cleanup(SocketServerInvoker.java:437)
>>>         at org.jboss.remoting.transport.socket.SocketServerInvoker.stop(SocketServerInvoker.java:404)
>>>         at org.jboss.remoting.transport.Connector.stop(Connector.java:1111)
>> At a glance LRUPool extends LRUCachePolicy which has a protected m_map
>> field. So for the moment I would say: Uh?
>>
> 
> I've tried
> 
> rm -rf ~/.m2/repository/org/jboss/remoting/
> rm -rf ~/.m2/repository/org/jboss/ejb3/
> 
> and did a clean build (including clobbering thirdparty). 
> 
> Still seeing the error.
> 
> Disassembling LRUCachePolicy, I can see the 
> protected field m_map
> 
> $ javap -c -classpath jboss-common-core.jar
> org.jboss.util.LRUCachePolicy
> Compiled from "LRUCachePolicy.java"
> public class org.jboss.util.LRUCachePolicy extends java.lang.Object
> implements org.jboss.util.CachePolicy{
> protected java.util.Map m_map;
> 
> Disassembing LRUPool, it is expecting a HashMap not a Map
> so this has obviously changed at some point.
> 
> $ javap -c -classpath jboss-remoting.jar
> org.jboss.remoting.transport.socket.LRUPool
> Compiled from "LRUPool.java"
> public class org.jboss.remoting.transport.socket.LRUPool extends
> org.jboss.util.LRUCachePolicy{
> 
> ...
> 
> public java.util.Set getContents();
>   Code:
>    0:   aload_0
>    1:   getfield        #12; //Field m_map:Ljava/util/HashMap;
>    4:   invokevirtual   #13; //Method
> java/util/HashMap.keySet:()Ljava/util/Set;
>    7:   areturn
> 
> So JBoss Remoting needs recompiling over the latest
> jboss-common-core
> 
> I don't know whether this fixes the other problems?
> 
>> Carlo
>>
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