Locked ldap threads

Our extend application gets more and more threads in a locked state as
time goes by. The thread dump shows that these have something to do with
ldap.
Sometimes there are also errors in the console "Ldap connection
unavailable" or something like that.

Is there a way to "reset" these without booting the whole application?
Using windows 2003, jboss, extend 5.2.1
The edirectory is on the same server and is working normally.

"Thread-25380" daemon prio=6 tid=0x638a8bc8 nid=0x2a04 runnable
[0x67e5f000..0x67e5fd6
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream. java:129)
at java.io.BufferedInputStream.fill(BufferedInputStre am.java:218)
at java.io.BufferedInputStream.read1(BufferedInputStr eam.java:256)
at java.io.BufferedInputStream.read(BufferedInputStre am.java:313)
- locked <0x4dc69668> (a java.io.BufferedInputStream)
at com.sun.jndi.ldap.Connection.run(Connection.java:7 84)
at java.lang.Thread.run(Thread.java:595)

"Thread-25316" daemon prio=6 tid=0x63a2b328 nid=0x2df0 runnable
[0x67f9f000..0x67f9fd6
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream. java:129)
at java.io.BufferedInputStream.fill(BufferedInputStre am.java:218)
at java.io.BufferedInputStream.read1(BufferedInputStr eam.java:256)
at java.io.BufferedInputStream.read(BufferedInputStre am.java:313)
- locked <0x4c0015d8> (a java.io.BufferedInputStream)
at com.sun.jndi.ldap.Connection.run(Connection.java:7 84)
at java.lang.Thread.run(Thread.java:595)

"Thread-25283" daemon prio=6 tid=0x780b98d8 nid=0x1b34 runnable
[0x67f1f000..0x67f1f9e