Need to write a client, which can scan the available WIFI networks and connects to best known using Java. This might be desktop client which does this job. Any pointers would be helpful and appreciate your response.
You'll have to rely on a JNI library since you can't access a wireless device directly in Java.
jWlanScan for Windows.
I suggest you to act upon your operating system. And for each of the supporting operating system try to analyse the results of the command lines needed to connect the wireless devices. It is quite straight forward and You will not have to work with JNI libraries.
For example for windows you can see the ones introduced here, here and here and for the linux it is still easier.
来源：https://stackoverflow.com/questions/12517765/scan-and-connect-to-wifi-networks-using-java