question: protected final void clean ( ) { if ( ! isAlive ( ) ) return ; synchronized ( this ) { _shouldDie = true ; notify ( ) ; } try { join ( ) ; } catch ( InterruptedException e ) { } if ( _expirationList != null ) _expirationList . clear ( ) ; }
target:  Wakes up, waits for reaper to die, and clears all lease mappings.