Hi,
I solved my first multi thread problem by having a shared RuleBase for
all threads. My problem is now with Objects insertion. Here is the trace
that occur :

java.lang.ArrayIndexOutOfBoundsException: 17
	at
org.drools.util.AbstractHashTable$HashTableIterator.next(AbstractHashTable.java:250)
	at org.drools.reteoo.Rete$ObjectTypeConf.buildCache(Rete.java:434)
	at org.drools.reteoo.Rete$ObjectTypeConf.getObjectTypeNodes(Rete.java:425)
	at org.drools.reteoo.Rete.assertObject(Rete.java:172)
	at org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:190)
	at
org.drools.reteoo.ReteooWorkingMemory.doInsert(ReteooWorkingMemory.java:70)
	at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:772)
	at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:584)
	at test.TestThreads$DroolsThread.run(TestThreads.java:65)
	at java.lang.Thread.run(Thread.java:534)

The program that I made to reproduce this error create threads that each
create a working memory from a static rule base (that works great) and
then insert some objects in this working memory. I have this error in a
real j2ee program.

Here is a listing of the code :

package test;

import java.io.IOException;
import java.io.InputStreamReader;

import org.drools.RuleBase;
import org.drools.RuleBaseFactory;
import org.drools.StatefulSession;
import org.drools.compiler.DroolsParserException;
import org.drools.compiler.PackageBuilder;
import org.drools.compiler.PackageBuilderConfiguration;

public class TestThreads {

    public static RuleBase rulebase;

    public static void main(String[] args) {
        PackageBuilderConfiguration pkgBuilderCfg =
            new PackageBuilderConfiguration();
        PackageBuilder builder = new PackageBuilder(pkgBuilderCfg);
        try {
            builder.addPackageFromDrl(new InputStreamReader(
                    TestThreads.class.getResourceAsStream( "Sample.drl" )));
        } catch (DroolsParserException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        rulebase = RuleBaseFactory.newRuleBase();
        try {
            rulebase.addPackage(builder.getPackage());
        } catch (Exception e) {
            e.printStackTrace();
        }
        for(int i = 0; i<100 ; i++) {
            DroolsThread tt = new DroolsThread("Thread " + i);
            new Thread(tt).start();
        }
    }

    public static class Fact {
        public String s;

        public Fact(String s){
            this.s = s;
        }

        public String getS() {
            return s;
        }
    }

    public static class DroolsThread implements Runnable {

        private String id;

        public DroolsThread(String id) {
            this.id = id;
        }

        public void run() {
            StatefulSession session = rulebase.newStatefulSession();
            for(int i = 0; i < 100; i++) {
                session.insert(new Fact(id));
            }
        }
    }
}

I am using Drools MR3.
Thanks for your help.
Pierre Paysant-Le Roux