My TCP/IP server socket is not accepting connections from other systems. When i try to send data from the client to server within the same system i see them working fine,
Here is what i get by printing the stacktraces -

  Waiting for client on port 50000...
 java.net.SocketTimeoutException: Accept timed out
 Socket timed out!
 Waiting for client on port 50000...
    at java.net.DualStackPlainSocketImpl.waitForNewConnection(Native Method)
    at java.net.DualStackPlainSocketImpl.socketAccept(DualStackPlainSocketImpl.java:125)
    at java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:398)
    at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:183)
    at java.net.ServerSocket.implAccept(ServerSocket.java:522)
    at java.net.ServerSocket.accept(ServerSocket.java:490)
    at tcpnet1.Tcpnet.run(Tcpnet.java:40)
 java.lang.NullPointerException
    at tcpnet1.Tcpnet.run(Tcpnet.java:49)
 java.net.SocketTimeoutException: Accept timed out
 Socket timed out!

Help me please

One possible cause is that your firewall is blocking the connections.

How do i check that and get through this problem?

You could try turning the firewall off for a quick moment and see if it works (don't forget to turn it back on a.s.a.p.).