FULL PRODUCT VERSION :
java version "1.8.0_40"
Java(TM) SE Runtime Environment (build 1.8.0_40-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.40-b25, mixed mode)

A DESCRIPTION OF THE PROBLEM :
When calling JSON.parse() on a string containing an object with keys that are numbers (as strings), it will fail with

java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 12



STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
jjs -scripting
jjs> var f = readFully("test.json");
jjs> JSON.parse(f);
java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 12

Test file contents:
{"1":7,"3":2,"5":4,"7":3,"11":11,"12":1,"13":3,"14":1,"17":4,"21":1,"31":2,"51":3,"80":6,"81":15,"91":5,"771":1,"1117":1,"1391":1,"1781":1,"11181":1,"BETTS":67,"BIRCH":226,"BIRCTI":1,"BISHOP":256}



REPRODUCIBILITY :
This bug can be reproduced always.