issue #345 better error for path segment missing in JSONPointer

Author: ryber

Diff for: unirest/src/main/java/kong/unirest/json/JSONPointer.java

@@ -178,6 +178,9 @@ public Object queryFrom(Object object) throws JSONPointerException {
         Queryable e = verify(object);
         Object o = e.querySection(section);
         if (next != null) {
+            if(o == null){
+                throw new JSONPointerException("Path Segment Missing: " + section);
+            }
             return next.queryFrom(o);
         }
         return o;

Diff for: unirest/src/test/java/kong/unirest/json/JSONPointerTest.java

@@ -51,6 +51,13 @@ public void invalidPathQuery() {
                 "a JSON pointer should start with '/' or '#/'");
     }
 
+    @Test
+    public void invalidPathQuery_downpath() {
+        TestUtil.assertException(() -> obj.query("/shwoop/dedoop"),
+                JSONPointerException.class,
+                "Path Segment Missing: shwoop");
+    }
+
     @Test
     public void arrayPartThatDoesNotExist() {
         TestUtil.assertException(() -> obj.query("/foo/5"),