Java APIs

I have a client server application.In the client part i send data to the server and the server receive data. After receiveing data server also send some data but the client can't capture data. Anyone please tell me what is the problem?

I am giving the sample code here......
I am thinking actually the problem is in the client side.......
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Server
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out = new DataOutputStream(client.getOutputStream());
input = this.client.getInputStream();


byte[] data=new byte[input.available()];
input.read(data);

byte[] sdata=new byte[3];
sdata[0]=1;
sdata[1]=2;
sdata[2]=3;
out.write(sdata);

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Client
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How can i implement my client to send and receive at a time??