I noticed a problem in the class ResilientFileOutputStream, used in FileAppender to create the output stream.

The class ResilientFileOutputStream has two output stream, a FileOutputStream and an OutputStream (instantiated with a BufferedOutputStream). The latter is inherited from the class ResilientFileOutputStreamBase that ResilientFileOutputStream extends. Since ResilientFileOutputStream has no close method, when a FileAppender is stopped the close method of ResilientFileOutputStreamBase gets called, this method only close the OutputStream.

Hence, when a FileAppender is stopped, the FileOutputStream of ResilientFileOutputStream is not closed. As a consequence, instances of FileAppender, ResilientFileOutputStream and FileOutPutStream are kept in memory even if they are no more used.