WOSessionStore$TimeoutEntry

we have a linux server running our web objects app. After a day, the system locks up for 30 mins. It will self-recoverbut in the mean time, nobody can log in or use the app. I have seen thread dumps during this period and I have noticed the following trace:


"http-20226-Processor24" daemon prio=1 tid=0x52321880 nid=0x593 in Object.wait() [0x51b7d000..0x51b7e120]
        at java.lang.Object.wait(Native Method)
        - waiting on <0xaaede7d8> (a com.webobjects.appserver.WOSessionStore$TimeoutEntry)
        at java.lang.Object.wait(Object.java:474)
        at com.webobjects.appserver.WOSessionStore.checkOutSessionWithID(WOSessionStore.java:191)
        - locked <0xaaede7d8> (a com.webobjects.appserver.WOSessionStore$TimeoutEntry)
        at com.webobjects.appserver.WOApplication.restoreSessionWithID(WOApplication.java:1904)

There are a lot of http threads in this state. There is one lock for every 4 http threads waiting on it.

Can any one explain what the above means?