i want to implement client server communication through wirless network in java,by using Socket,ServerSocket classes can i connect two computers with wireless connection???

Not with pure Java, no. The ad-hoc network will already have to exist and then you can use it to connect from one to the other, yes.

i have listened that if u are using sockets,then the systems must be connected through lan physically......is that not true,can u help me in transfering files from one system to another system which are connected in a wireless network??

They have to be connected through a network. Whether that network is a "cable" network, or a "wireless" network is irrelevant. "cable" is not what is meant by "physically". "Physically", in that statement, means that an actual network connection exists, but it must be a "real", standard network connection.

ohk then it will work for both wired and wireless nwtworks......thanks......can u help me in implementing file transfer in wireless network??