I searched and found:
A recursive function that will search (starting from the root window) for a window with the desired name
Window windowWithName(Display *dpy, Window top, char *name)
{
Window *children, dummy;
unsigned int nchildren;
unsigned int i;
Window w = 0;
char *window_name;
if (XFetchName(dpy, top, &window_name) && !strcmp(window_name, name))
return (top);
if (!XQueryTree(dpy, top, &dummy, &dummy, &children, &nchildren))
return (0);
for (i = 0; i < nchildren; i++)
{
w = windowWithName(dpy, children[i], name);
if (w)
break;
}
if (children)
XFree((char *) children);
return (w);
}
You can always open a java.net.Socket
to port 6000 or so and speak X11
yourself.
code that might help
reference, hope this help
NOTE: package sun.awt.x11
is no more in jdk7