Java Programming

Hello

Finally I ask here my question because I already looked evryhere to find a solution to my Problem.
I have the following issue:
I work in a Websphere Application Server and AIX environment and I develop an Ldap API that is used in order to access a directory.
But I have to deal with the fact that sometimes the directory goes down. When this is the case, the DNS alias is changed to point on the second directory, but you gess it, the JVM keeps the old IP address.
I found the property networkaddress.cache.ttl, that seems to solve my troubles, but that doesn't work.
The point is that I don't want to restart the Websphere Application Server, I want to force the JVM to make a real DNS lookup and this in my code, not passing the property on the java command line.
Is there a way to do this ??

Thank you very much for your help