Test fix

examples/javawlp_edsl/src/nl/uu/javawlp_edsl/Main.java

@@ -104,7 +104,6 @@ public class Main {
     }
 
     public static void swap_spec4(int[] a, int i, int j) {
-        pre(a != null);
         pre(a.length > 0);
         pre(i >= 0);
         pre(j >= 0);