Thread Safe issue in MonitorPlugin creating deadlock on the wiki farm

"TP-Processor72" daemon prio=1 tid=0x08a611d8 nid=0x1937 runnable [0xa3f58000..0xa3f597c0]
at java.util.HashMap.put(HashMap.java:385)
at com.xpn.xwiki.store.XWikiHibernateBaseStore.addConnection(XWikiHibernateBaseStore.java:520)
at com.xpn.xwiki.store.XWikiHibernateBaseStore.beginTransaction(XWikiHibernateBaseStore.java:498)
at com.xpn.xwiki.store.XWikiHibernateBaseStore.beginTransaction(XWikiHibernateBaseStore.java:446)
at com.xpn.xwiki.store.XWikiHibernateStore.exists(XWikiHibernateStore.java:167)

"TP-Processor81" daemon prio=1 tid=0x08c3f598 nid=0x19a2 runnable [0xa457e000..0xa457f6c0]
at java.util.HashMap.removeEntryForKey(HashMap.java:560)
at java.util.HashMap.remove(HashMap.java:530)
at com.xpn.xwiki.store.XWikiHibernateBaseStore.removeConnection(XWikiHibernateBaseStore.java:530)
at com.xpn.xwiki.store.XWikiHibernateBaseStore.closeSession(XWikiHibernateBaseStore.java:588)
at com.xpn.xwiki.store.XWikiHibernateBaseStore.endTransaction(XWikiHibernateBaseStore.java:570)
at com.xpn.xwiki.store.XWikiHibernateStore.exists(XWikiHibernateStore.java:193)

We probably need a synchronized hashmap