Add another test

src/test/java/org/json/junit/JSONPointerTest.java

@@ -74,6 +74,14 @@ public class JSONPointerTest {
             query("/obj//")
         );
     }
+    
+    @Test
+    public void queryByEmptyKeySubObjectValue() {
+        assertSame(
+            document.getJSONObject("obj").getJSONObject("").get("subKey"),
+            query("/obj//subKey")
+        );
+    }
 
     @Test
     public void slashEscaping() {

src/test/resources/jsonpointer-testdoc.json

@@ -20,6 +20,9 @@
 				"val"
 			]
 		},
-		"" : { "" : "empty key of an object with an empty key" }
+		"" : {
+		    "" : "empty key of an object with an empty key",
+		    "subKey" : "Some other value"
+		}
 	}
 }