question: public void insert ( Transaction transaction ) { LOG . debug ( "about to insert: " + transaction ) ; if ( ! transaction . isEmpty ( ) ) { List < Transaction > tail = new ArrayList < > ( mTransactions . size ( ) + 2 ) ; mTransactions . drainTo ( tail ) ; mTransactions . add ( transaction ) ; mTransactions . addAll ( tail ) ; } }
target:  Adds a transaction to the beginning of the queue. Note that actions of the *currently executing* transaction will still be executed before the given transaction.