diff --git a/src/test/java/org/json/junit/CookieListTest.java b/src/test/java/org/json/junit/CookieListTest.java
index 80cbaa8..7149644 100644
--- a/src/test/java/org/json/junit/CookieListTest.java
+++ b/src/test/java/org/json/junit/CookieListTest.java
@@ -65,7 +65,7 @@ public class CookieListTest {
     public void emptyStringCookieList() {
         String cookieStr = "";
         JSONObject jsonObject = CookieList.toJSONObject(cookieStr);
-        assertTrue(jsonObject.length() == 0);
+        assertTrue(jsonObject.isEmpty());
     }
 
     /**
diff --git a/src/test/java/org/json/junit/EnumTest.java b/src/test/java/org/json/junit/EnumTest.java
index cd0d8c0..366643e 100644
--- a/src/test/java/org/json/junit/EnumTest.java
+++ b/src/test/java/org/json/junit/EnumTest.java
@@ -35,7 +35,7 @@ public class EnumTest {
         // If there are no getters then the object is empty.
         MyEnum myEnum = MyEnum.VAL2;
         JSONObject jsonObject = new JSONObject(myEnum);
-        assertTrue("simple enum has no getters", jsonObject.length() == 0);
+        assertTrue("simple enum has no getters", jsonObject.isEmpty());
 
          // enum with a getters should create a non-empty object 
         MyEnumField myEnumField = MyEnumField.VAL2;
diff --git a/src/test/java/org/json/junit/JSONArrayTest.java b/src/test/java/org/json/junit/JSONArrayTest.java
index 8a31c87..845f4e7 100644
--- a/src/test/java/org/json/junit/JSONArrayTest.java
+++ b/src/test/java/org/json/junit/JSONArrayTest.java
@@ -691,7 +691,7 @@ public class JSONArrayTest {
         JSONArray jsonArray = new JSONArray(arrayStr1);
         jsonArray.remove(0);
         assertTrue("array should be empty", null == jsonArray.remove(5));
-        assertTrue("jsonArray should be empty", jsonArray.length() == 0);
+        assertTrue("jsonArray should be empty", jsonArray.isEmpty());
     }
 
     /**
diff --git a/src/test/java/org/json/junit/JSONObjectTest.java b/src/test/java/org/json/junit/JSONObjectTest.java
index 5dc31c7..e3b9529 100644
--- a/src/test/java/org/json/junit/JSONObjectTest.java
+++ b/src/test/java/org/json/junit/JSONObjectTest.java
@@ -141,7 +141,7 @@ public class JSONObjectTest {
     @Test
     public void emptyJsonObject() {
         JSONObject jsonObject = new JSONObject();
-        assertTrue("jsonObject should be empty", jsonObject.length() == 0);
+        assertTrue("jsonObject should be empty", jsonObject.isEmpty());
     }
 
     /**
@@ -184,7 +184,7 @@ public class JSONObjectTest {
     public void jsonObjectByNullMap() {
         Map<String, Object> map = null;
         JSONObject jsonObject = new JSONObject(map);
-        assertTrue("jsonObject should be empty", jsonObject.length() == 0);
+        assertTrue("jsonObject should be empty", jsonObject.isEmpty());
     }
 
     /**
@@ -1122,7 +1122,7 @@ public class JSONObjectTest {
         BigDecimal bigDecimal = new BigDecimal(
                 "123456789012345678901234567890.12345678901234567890123456789");
         jsonObject = new JSONObject(bigDecimal);
-        assertTrue("large bigDecimal is not stored", jsonObject.length() == 0);
+        assertTrue("large bigDecimal is not stored", jsonObject.isEmpty());
 
         /**
          * JSONObject put(String, Object) method stores and serializes
@@ -2244,11 +2244,11 @@ public class JSONObjectTest {
     public void jsonObjectPutOnceNull() {
         JSONObject jsonObject = new JSONObject();
         jsonObject.putOnce(null, null);
-        assertTrue("jsonObject should be empty", jsonObject.length() == 0);
+        assertTrue("jsonObject should be empty", jsonObject.isEmpty());
         jsonObject.putOnce("", null);
-        assertTrue("jsonObject should be empty", jsonObject.length() == 0);
+        assertTrue("jsonObject should be empty", jsonObject.isEmpty());
         jsonObject.putOnce(null, "");
-        assertTrue("jsonObject should be empty", jsonObject.length() == 0);
+        assertTrue("jsonObject should be empty", jsonObject.isEmpty());
     }
 
     /**
@@ -2424,11 +2424,11 @@ public class JSONObjectTest {
         String str = "{\"myKey\": \"myval\"}";
         JSONObject jsonObjectRemove = new JSONObject(str);
         jsonObjectRemove.remove("myKey");
-        assertEquals("jsonObject should be empty",0 ,jsonObjectRemove.length());
+        assertTrue("jsonObject should be empty", jsonObjectRemove.isEmpty());
 
         JSONObject jsonObjectPutNull = new JSONObject(str);
         jsonObjectPutNull.put("myKey", (Object) null);
-        assertEquals("jsonObject should be empty",0 ,jsonObjectPutNull.length());
+        assertTrue("jsonObject should be empty", jsonObjectPutNull.isEmpty());
 
 
     }
diff --git a/src/test/java/org/json/junit/PropertyTest.java b/src/test/java/org/json/junit/PropertyTest.java
index 60d3eb5..8804284 100644
--- a/src/test/java/org/json/junit/PropertyTest.java
+++ b/src/test/java/org/json/junit/PropertyTest.java
@@ -21,7 +21,7 @@ public class PropertyTest {
     public void shouldHandleNullProperties() {
         Properties properties = null;
         JSONObject jsonObject = Property.toJSONObject(properties);
-        assertTrue("jsonObject should be empty", jsonObject.length() == 0);
+        assertTrue("jsonObject should be empty", jsonObject.isEmpty());
     }
 
     /**
@@ -32,7 +32,7 @@ public class PropertyTest {
     public void shouldHandleEmptyProperties() {
         Properties properties = new Properties();
         JSONObject jsonObject = Property.toJSONObject(properties);
-        assertTrue("jsonObject should be empty", jsonObject.length() == 0);
+        assertTrue("jsonObject should be empty", jsonObject.isEmpty());
     }
 
     /**
diff --git a/src/test/java/org/json/junit/XMLTest.java b/src/test/java/org/json/junit/XMLTest.java
index c34bf0f..651d1a7 100644
--- a/src/test/java/org/json/junit/XMLTest.java
+++ b/src/test/java/org/json/junit/XMLTest.java
@@ -34,7 +34,7 @@ public class XMLTest {
     public void shouldHandleNullXML() {
         String xmlStr = null;
         JSONObject jsonObject = XML.toJSONObject(xmlStr);
-        assertTrue("jsonObject should be empty", jsonObject.length() == 0);
+        assertTrue("jsonObject should be empty", jsonObject.isEmpty());
     }
 
     /**
@@ -45,7 +45,7 @@ public class XMLTest {
 
         String xmlStr = "";
         JSONObject jsonObject = XML.toJSONObject(xmlStr);
-        assertTrue("jsonObject should be empty", jsonObject.length() == 0);
+        assertTrue("jsonObject should be empty", jsonObject.isEmpty());
     }
 
     /**
@@ -55,7 +55,7 @@ public class XMLTest {
     public void shouldHandleNonXML() {
         String xmlStr = "{ \"this is\": \"not xml\"}";
         JSONObject jsonObject = XML.toJSONObject(xmlStr);
-        assertTrue("xml string should be empty", jsonObject.length() == 0);
+        assertTrue("xml string should be empty", jsonObject.isEmpty());
     }
 
     /**
@@ -200,7 +200,7 @@ public class XMLTest {
     public void shouldHandleEmptyJSONXML() {
         JSONObject jsonObject= new JSONObject();
         String xmlStr = XML.toString(jsonObject);
-        assertTrue("xml string should be empty", xmlStr.length() == 0);
+        assertTrue("xml string should be empty", xmlStr.isEmpty());
     }
 
     /**