Can I use MonitorAll for browser based applications (in my case it is java applet application)? If yes, let me know if any precautions to take care and is there any disadvantages in terms of performance (memory usage etc), hooking etc.
Can I use MonitorAll for multiple web adapters in the same solution?
Yes. The only thing to remember with MonitorAll is that it requires the user to bring up the application - starting the adapter does not start the application. There shouldn't be any disadvantages in performance.
If you just want to use your Web Adapter, you can set the property HookChildProcesses=True on the Web Adapter in order to hook into the application when it is started.