We have writen a MBEAN such as posted in the JBoss3.x docu: A Standard MBean Example page 118. (see code below)
This worked wounderfull in JBoss3.2.3.
After adapting the jboss-service.xml I was able to deploy it in JBoss4.0.0.
Using the jmx-Console I am able to view all the properties stored in the MBean. But when I try to connect to the MBean using JDNI

 Context ctx = new InitialContext();
 serverSettings = (ServerSettings)ctx.lookup("java:/MARSServerSettings");

from my application (inside Jboss) I am able to invoke the bean and its methods, but the returned properties are null.

Has anyone an idea whats the problem ?
It seems to me that the MBean is not a singleton anymore!

Cheers Michael

public interface ServerSettingsMBean extends java.io.Serializable {
 public static final int STOPPED = 0;
 public static final int STARTED = 1;

 public void setProperty(String key, String value);
 public void removeProperty(String key);
 public String getProperty(String key);
 public String listProperties();
 public String[] getKeys();
 public void setJNDIName(String jndiName);
 public String getJNDIName();
 public String getStatusString();
 public int getStatus();
 public void start();
 public void stop();
}

public class ServerSettings implements ServerSettingsMBean {
 private static final String TABLENAME = "MARSSERVERPROPERTIES";

 private String JNDIName_ = "not set";
 private int status_ = STOPPED;
 private java.util.Hashtable properties_ = new java.util.Hashtable();
 private transient Connection con_ = null;



 public void setProperty(String key, String value) {
 setPropertyDB(key.trim(),value.trim());
 properties_.put(key.trim(), value.trim());
 }

 public String getProperty(String key) {
 System.out.println("ServerSettings-getProperty "+key);
 String retValue = (String)properties_.get(key.trim());
 System.out.println("ServerSettings-getProperty returns "+retValue);
 return retValue;
 }
.......
}

<server>
 <mbean code="at.tugraz.genome.marsservice.ServerSettings"
 name="at.tugraz.genome.marsservice:service=ServerSettings">
 <attribute name="JNDIName">java:/MARSServerSettings</attribute>
 <depends>jboss.jca:service=DataSourceBinding,name=jdbc/DefaultDS</depends>
 <!--depends>jboss.jca:service=XATxCM,name=jdbc/DefaultDS</depends>
 <depends>jboss.jca:service=ManagedConnectionFactory,name=jdbc/DefaultDS</depends>
 <depends>jboss.jca:service=ManagedConnectionPool,name=jdbc/DefaultDS</depends-->
 </mbean>
</server>