Are you sure you're looking at the right source, and not just a compiled class in your IDE. I have the following:
/**
* A constant holding the minimum value an {@code int} can
* have, -2<sup>31</sup>.
*/
public static final int MIN_VALUE = 0x80000000;
/**
* A constant holding the maximum value an {@code int} can
* have, 2<sup>31</sup>-1.
*/
public static final int MAX_VALUE = 0x7fffffff;
Grep code agrees: http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/6-b14/java/lang/Integer.java