question: public void shutdown ( ) { if ( VERBOSE ) Util . verbose ( "Shutdown" ) ; disable ( ) ; discardJobs ( null ) ; Thread thread = this . processingThread ; try { if ( thread != null ) { synchronized ( this ) { this . processingThread = null ; notifyAll ( ) ; } thread . join ( ) ; } Job job = this . progressJob ; if ( job != null ) { job . cancel ( ) ; job . join ( ) ; } } catch ( InterruptedException e ) { } }
target:  Stop background processing, and wait until the current job is completed before returning