ANT style wildcard.
To include just *.java, set filter type to "Include" and type add "*.java" (without quote) in the wildcard. To exclude *.exe" and all JUnit test cases, set filter type to "Exclude" and add two wildcard, one for "*.dll" and one for "*Test*"
To exclude a directory, set filter to "**/dir_to_exclude/**"
Note: (1) the wildcard is case insensitive, (2) all backslashes (\) will be replaced with slashes (/)