Closing operation problem

Question

i face a problem on closing a calling class operation and pls help me cause i need it to complete my double module project... the below is a sample coding (note: i dun wan to close the window(System.exit) only for the specify class finction)
// this is an calling class (call stegaBmp class)
hideFile = stegaBmp.performBmpHide(new File(HidenPathField.getText()),
smsPathFile, pass, tempFile, comboBox.getSelectedItem().toString());
// this is the function class which i wanna close when (comboBox.equals("PHASE + LSB"))
public class BmpStegaHide {
public File performBmpHide(File bmpfile, File msgfile, String pass, File tempfile, String comboBox) throws
StegaException {
File hidefile;
try {
if (comboBox.equals("PHASE + LSB")){
JOptionPane.showMessageDialog(null,"The size of the first file must be at least ");
//Close the BmpStegaHide class here @@@@@@@ anyone can help (not System.exit or dispose()
}

Answer 1

i wanna terminate all the operation on class BmpstegaHide when the variable comboBox == "LSB" which passing from other class to bmpstegahide class... can u understand what i mean?? thx for helping
public class BmpStegaHide {
public File performBmpHide(File bmpfile, File msgfile, String pass, File tempfile, String comboBox) throws
StegaException {
if comboBox.equals("LSB")
System.exit(0) ///this method will also exit the main frame so i dun wan (i also try dispose() but also cannot)
}