JimNLP (Java Implementation for Natural Language Processing) is a platform that facilitate NLP research such as Information Extrction, Summarization and Text Entailment etc.
Since 2009, I began to develop this platform to facilicate my NLP research. I maintained it until I got my PhD in 2012. Four top level conferences including ACL and EMNLP got benefits from this platform. Key features include several topic model variants, a lightweight feature engineering inspired by mallet, rich data structures for NLP, clustering and ranking algorithms and some useful tools.
Check the conference folder to see how to use the platform to construct abstractive summarization system. More theoretical details can be found at "Weakly Supervised Natural Language Processing Framework for Abstractive Multi-Documents Summarization"(CIKM2015)