question: public synchronized void clearTransactions ( Date fromDate ) { lock . lock ( ) ; try { if ( fromDate == null ) { unspent . clear ( ) ; spent . clear ( ) ; pending . clear ( ) ; dead . clear ( ) ; } else { removeEntriesAfterDate ( unspent , fromDate ) ; removeEntriesAfterDate ( spent , fromDate ) ; removeEntriesAfterDate ( pending , fromDate ) ; removeEntriesAfterDate ( dead , fromDate ) ; } } finally { lock . unlock ( ) ; } }
target:  Deletes transactions which appeared after a certain date