make EXISTS test work with collections

json-path/src/main/java/com/jayway/jsonpath/Criteria.java

@@ -221,16 +221,26 @@ public class Criteria {
 
             } else if (CriteriaType.EXISTS.equals(key)) {
 
-                boolean exp = (Boolean) expectedVal;
+              final boolean exp = (Boolean) expectedVal;
+              return objectOrAnyCollectionItemMatches(map, new Predicate<Object>() {
+
+                @Override
+                public boolean accept(final Object value) {
                   boolean act = true;
-                try{
-                  this.key.read(map);
-                }catch (InvalidPathException e){
+                  try {
+                    Object val = getKey().read(value);
+                    if(val instanceof Collection){
+                      act = !((Collection) val).isEmpty();
+                    }
+                  } catch (InvalidPathException e) {
                     act = false;
                   }
-
                   return act == exp;
 
+                }
+
+              });
+
             } else if (CriteriaType.TYPE.equals(key)) {
 
                 Class<?> exp = (Class<?>) expectedVal;