In tinySQLResultSet, various get methods (getByte, getBoolean) work via getString. Only some of these methods check against a null string. An invalid column results in getString returning a null string, subsequently resulting in a NullPointerException in str.compare.
Found on version 2.26 under Mac OS 10.9, Java 6 and Java 7. The attached test is in JUnit format.
The fix is easy: Add
if( str == null ) return 0;
as in similar methods (getShort), which do not have this issue.