How can i manually unload a library that i load using System.loadLibrary command without close browser.

I don't know of a way to do that, but if you own the code in question, you might want to redesign hte problem a little bit.

I assume that it is a resource-heavy library or that you want to do some fancy thnigs by dynamically changing the implementation at runtime. You can load an intermediate library which just acts as a loader for the real library. This intermediate library would offer a native API to unload/reload the real library.

What is your reason for trying to unload the library?