Java - Validacion checkbox

if (e.getSource() == btnProces) {

	if (check1.isSelected() == false && check2.isSelected() == false && check3.isSelected() == false && check4.isSelected() == false){

		JOptionPane.showMessageDialog(null, "please choose the specification"

		 );

	}

	if (check1.isSelected() == true) {

		JOptionPane.showMessageDialog(null, "check1"

		 );

	}

	if (check2.isSelected() == true) {

		JOptionPane.showMessageDialog(null, "check2"

		 );

	}

	if (check3.isSelected() == true) {

		JOptionPane.showMessageDialog(null, "check3"

		 );

	}

	if (check4.isSelected() == true) {

		JOptionPane.showMessageDialog(null, "check4"

		 );

	}

}