Are you trying to update a node type ? You're unregistering and then reqistering a node type with the "update" flag to false. If you're trying to update a node type, the "update" flag has to be set to "true".
In any case, you should try using the latest 4.6.0.Final since ModeShape 3 is aprox 2 years old and with potentially lots of bugs.
As there are are lot changes in nodeType so I am first unregistering the old type and then registering the new updated type.
However this update of the node type is not persisting. So when I my restart my server I dont see the new nodeType I still get the old nodeType.
Right now due to some restrictions I can't update the modeshape version.
Please help how can I re-register the nodeType in Modeshape-3.7.1-FINAL version itself.
The correct way to update a node type is: nodeTypeManager.registerNodeType(type, true) (see my previous comment)
If with this change the code still doesn't work, you'll have to investigate (debug) and patch the code yourself locally.