FULL PRODUCT VERSION :
java version "1.7.0"
Java(TM) SE Runtime Environment (build 1.7.0-b147)
Java HotSpot(TM) Client VM (build 21.0-b17, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
It's not clear whether MalformedInputException.getInputLength() refers to the total number of string/bytes that were being encoded/decoded or exclusively to the the subsequence that was malformed.

http://download.oracle.com/javase/7/docs/api/java/nio/charset/MalformedInputException.html#getInputLength()

REPRODUCIBILITY :
This bug can be reproduced always.