src/java.desktop/unix/native/libawt_xawt/awt/awt_Robot.c

@@ -147,11 +147,11 @@
 }
 
 static jboolean isXCompositeDisplay(Display *display, int screenNumber) {
 
     char NET_WM_CM_Sn[25];
-    snprintf(NET_WM_CM_Sn, sizeof(NET_WM_CM_Sn), "_NET_WM_CM_S%d\0", screenNumber);
+    snprintf(NET_WM_CM_Sn, sizeof(NET_WM_CM_Sn), "_NET_WM_CM_S%d", screenNumber);
 
     Atom managerSelection = XInternAtom(display, NET_WM_CM_Sn, 0);
     Window owner = XGetSelectionOwner(display, managerSelection);
 
     return owner != 0;