ANTLR - one of the most powerful parser generators. Used to parse input text and build tree described in TreeDL. ANTLR has built-in facilities for constructing and processing of trees, but they are focused on homogeneous trees and tree grammars. TreeDL supplements ANTLR in th field of heterogeneous trees processing.
SableCC - interesting compiler generator that produces parsers, strictly-typed abstract syntax tree descriptions and tree walkers (visitors).
Eclipse - one of the best Java development environments. The plugin for integration TreeDL into Eclipse is available.