Divide & Conquer

public class dlgInput extends javax.swing.JDialog {
	private javax.swing.JButton btnAceptar;
	private javax.swing.JTextField input;
	private javax.swing.JScrollPane jScrollPane1;
	private javax.swing.JTextArea txtInformacion;
 
	public dlgInput(java.awt.Frame parent, boolean modal, String texto, String titulo) {
		super(parent, modal);
		initComponents();
		txtInformacion.setText(texto);
		setTitle(titulo);
		setLocationRelativeTo(null);
		setVisible(true);
	}
 
	public dlgInput(java.awt.Dialog parent, boolean modal, String texto, String titulo) {
		super(parent, modal);
		initComponents();
		txtInformacion.setText(texto);
		setTitle(titulo);
		setLocationRelativeTo(null);
		setVisible(true);
	}
 
	public String getResponse(){
		return this.input.getText();
	}
 
	private void initComponents() {
		jScrollPane1 = new javax.swing.JScrollPane();
		txtInformacion = new javax.swing.JTextArea();
		btnAceptar = new javax.swing.JButton();
		input = new javax.swing.JTextField();
 
		setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
		setResizable(false);
 
		txtInformacion.setBackground(new java.awt.Color(240, 240, 240));
		txtInformacion.setColumns(20);
		txtInformacion.setEditable(false);
		txtInformacion.setFont(new java.awt.Font("Tahoma", 0, 12));
		txtInformacion.setLineWrap(true);
		txtInformacion.setRows(3);
		txtInformacion.setWrapStyleWord(true);
		jScrollPane1.setViewportView(txtInformacion);
 
		btnAceptar.setText("Aceptar");
		btnAceptar.addActionListener(new java.awt.event.ActionListener() {
			public void actionPerformed(java.awt.event.ActionEvent evt) {
				btnAceptarActionPerformed(evt);
			}
		});
 
		javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
		getContentPane().setLayout(layout);
		layout.setHorizontalGroup(
			layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
			.addGroup(layout.createSequentialGroup()
			.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
			.addGroup(layout.createSequentialGroup()
			.addContainerGap()
			.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 265, Short.MAX_VALUE))
			.addGroup(layout.createSequentialGroup()
			.addContainerGap()
			.addComponent(input, javax.swing.GroupLayout.DEFAULT_SIZE, 265, Short.MAX_VALUE))
			.addGroup(layout.createSequentialGroup()
			.addGap(94, 94, 94)
			.addComponent(btnAceptar)))
			.addContainerGap())
		);
		layout.setVerticalGroup(
			layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
			.addGroup(layout.createSequentialGroup()
			.addContainerGap()
			.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
			.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
			.addComponent(input, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
			.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
			.addComponent(btnAceptar)
			.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
		);
 
		pack();
	}
	private void btnAceptarActionPerformed(java.awt.event.ActionEvent evt) {                               
		this.setVisible(false);
	}                                              
}

	dlgInput a = new dlgInput(Dialog OR Frame, true, "Ingrese la cantidad.", "Agregar articulo a venta actual");
	int cantidad = Integer.valueOf(a.getResponse());
	a.dispose();