HouseSpider
HouseSpider is designed for use in applets, so probably is not suitable. However, it is released under the GPL licence. It has no dependencies beyond the standard Java class library, the package only has 14 classes.
Initial review notes
HouseSpider is a relatively advanced site search applet in so far as it generates and searches index files, but it is limited by its intended usage. Much of the HTML parsing and metadata extraction uses fairly rigid string matching. There is some food for thought, such as handling the HTML base
element for relative URLs, but overall HouseSpider will not be suitable for the MKSearch project.
Copyright MKDoc Ltd. and others.
The Free Documentation License http://www.gnu.org/copyleft/fdl.html