diff -r 2c45f75a5406 Lib/test/test_int_overflow_jy.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Lib/test/test_int_overflow_jy.py	Mon Aug 04 15:55:42 2014 +1000
@@ -0,0 +1,24 @@
+"""Int overflow tests
+
+Tests for int overflow on new style classes.
+"""
+import unittest
+import types
+from test import test_support
+
+class IntOverflowTest(unittest.TestCase):
+    def test_new_class_len_overflow(self):
+	class X(object):
+	    def __len__(self):
+	        return 2 ** 70
+        x = X()
+	with self.assertRaises(OverflowError) as context:
+            len(x)
+
+def test_main():
+    test_support.run_unittest(IntTestCase)
+
+if __name__ == '__main__':
+    test_main()
+
+
diff -r 2c45f75a5406 src/org/python/core/PyObjectDerived.java
--- a/src/org/python/core/PyObjectDerived.java	Mon Jul 14 14:19:57 2014 -0600
+++ b/src/org/python/core/PyObjectDerived.java	Mon Aug 04 15:55:42 2014 +1000
@@ -834,9 +834,7 @@
         PyObject impl=self_type.lookup("__len__");
         if (impl!=null) {
             PyObject res=impl.__get__(this,self_type).__call__();
-            if (res instanceof PyInteger)
-                return((PyInteger)res).getValue();
-            throw Py.TypeError("__len__ should return a int");
+            return res.asInt();
         }
         return super.__len__();
     }