Here I check whether node exist or not if(node==null){ | node = rootNode.addChild(someFqn); | } and here I put object into the node: node.put(key, obj); But what if eviction happened between those 2 parts of code? How can I defend myself agains NullPointerException? Please,suggest, what is best practice, excluding try/catch...? Thanks! Peter. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4153372#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...