TreeMap returns wrong key in lastKey function through interface SortedMap

Problem
=======
TreeMap returns wrong key in lastKey function through interface SortedMap when the map size is 65 and submap size is 64.

Test to reproduce the error
===================
import java.util.*;

public class Main {

static TreeMap<Integer,Integer> map;

static boolean test_passed = true;

public static void test_lastKey() {
SortedMap<Integer,Integer> s_map;

for(int i=0; i<65; i++)
map.put(i, i);

s_map = map.subMap(0, 64);

int last_key = s_map.lastKey();
if (last_key != 63)

{ test_passed = false; System.out.println("Error occured for map size: " + 65 + " submap(0, " + 64 + ")"); }

map.clear();
}

public static void main(String args[])

{ map = new TreeMap<Integer,Integer>(); System.out.println("test started!"); test_lastKey(); if (test_passed) System.out.println("test passed!"); }

}

Proposed fix
==========
Search the string "foundIndex = foundNode.right_idx - 1" in TreeMap.java,
and change it to "foundIndex = foundNode.right_idx".