During the last years, the software engineering research community has proposed approaches for automatically repairing software bugs. Unfortunately, many software artifacts born from this research are not available for repairing Java programs. To-reimplement those approaches from scratch is costly. To facilitate experimental replications and comparative evaluations, we present Astor, a publicly available program repair library that includes the implementation of three notable repair approaches (jGenProg, jKali and jMutRepair). We envision that the research community will use Astor for setting up comparative evaluations and explore the design space of automatic repair for Java. Astor offers researchers ways to implement new repair approaches or to modify existing ones. Astor repairs in total 33 real bugs from four large open source projects.