FULL PRODUCT VERSION :
mustang early release (java.net)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

EXTRA RELEVANT SYSTEM CONFIGURATION :
not needed

A DESCRIPTION OF THE PROBLEM :
In com.sun.rowset.CacheRowsetImpl and com.sun.rowset.JdbcRowsetImpl

   public void setMatchColumn(String columnName) throws SQLException {
        // validate, if col is ok to be set
        columnName = columnName.trim();
        if( columnName == "" || columnName.equals(null)) {
            throw new SQLException(resBundle.handleGetObject("cachedrowsetimpl.matchcols2").toString());

this guard

if( columnName == "" || columnName.equals(null)) {


is complelely bogus, if columnName is null both sides would cause a NullPointerException.



REPRODUCIBILITY :
This bug can be reproduced always.