what is the best and fastest way to communicate between two applications?

I made a java program just for fun this program allows you to control the seconds computer mouse using the first computer's mouse. so everytime the mouse moves some the x and the y of the cursor is sent client application. which then uses the robot class to move the mouse. right now I am using sockets to communicate and it is really slow what is a better way to do it any help would be apritited. if possible please provide some code thanks

Solution

If both applications live in different virtual machines, then communication via sockets is a very good approach.

If it is too slow, you may consider

using UDP protocol instead of TCP/IP
look at you server/client code, performance may be killed there.

Considering you comment to this answer:

As you send bytes over sockets, performance will be increased if you encode the mouse positions to byte values rather then to String:

int x = getX();
int y = getY();
// let's assume we have a 16Bit / 2Byte range for both values (practica)
byte[] message = new byte[4];
message[0] = (byte) (x >> 8) & 0xff;
message[1] = (byte) x & 0xff;
message[2] = (byte) (y >> 8) & 0xff;
message[3] = (byte) y & 0xff;
sendViaSocket(message);

(It starts and ends with some magic, the point is the encoding)