private void returnButtonActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_returnButtonActionPerformed
        ExecutorService returnExecutor = Executors.newCachedThreadPool();
        LibraryManager.ReturnTask bt = lfq.new ReturnTask();
        
        bt.getReturnTitle(titleField.getText().trim());

        returnExecutor.execute(bt);
        
        returnExecutor.shutdown();
        
        while (!returnExecutor.isTerminated()) {
           
        }
        
        JOptionPane.showMessageDialog(null, titleField.getText() + 
                " has been returned", "SUCCESS", JOptionPane.INFORMATION_MESSAGE);
    }//GEN-LAST:event_returnButtonActionPerformed