fix(#887): allow null value strict mode

Author: rikkarth

src/main/java/org/json/JSONTokener.java

@@ -527,7 +527,7 @@ private Object parsedUnquotedText(char c, boolean strictMode) {
     }
 
     private Object getValidNumberOrBooleanFromObject(Object value) {
-        if (value instanceof Number || value instanceof Boolean) {
+        if (value instanceof Number || value instanceof Boolean || value.equals(JSONObject.NULL)) {
             return value;
         }
 

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

@@ -75,6 +75,13 @@ public void givenInvalidString_testStrictModeTrue_shouldThrowJsonException() {
         assertEquals("Value is not surrounded by quotes: badString", je.getMessage());
     }
 
+    @Test
+    public void allowNullInStrictMode() {
+        String expected = "[null]";
+        JSONArray jsonArray = new JSONArray(expected, new JSONParserConfiguration().withStrictMode(true));
+        assertEquals(expected, jsonArray.toString());
+    }
+
     @Test
     public void shouldHandleNumericArray() {
         String expected = "[10]";