GenealogyJ is a viewer and editor for genealogic data, suitable for hobbyist, family historian and genealogy researcher. GenJ supports the Gedcom standard, is written in Java and offers many views like family tree, table, timeline, geography and more.
GDBI is a genealogy program integrator. It includes an editor and the lifelines report language. It interfaces to multiple GEDCOM databases and is most popular as a PhpGedView client. At the core is a Java API to simplify adding databases and editors.
Genepool is a Java and SQL based geneaology software, designed to be user-friendly but powerful at the same time. It will also be able to output to a variety of formats, and be able to combine several trees into a big one.