Press shift space or shift F2 to move the focus to the previous focusable component. : InputMap « Swing Event « Java Tutorial

1. Java Tutorial
2. Swing Event
3. InputMap

import java.awt.Component;
import java.awt.event.ActionEvent;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.KeyStroke;

public class Main {
  public static void main(String[] argv) {
    JButton component = new JButton();
    PrevFocusAction prevFocusAction = new PrevFocusAction();
    component.getInputMap(JComponent.WHEN_FOCUSED).put(KeyStroke.getKeyStroke("shift F2"),
        prevFocusAction.getValue(Action.NAME));
    component.getInputMap(JComponent.WHEN_FOCUSED).put(KeyStroke.getKeyStroke("shift SPACE"),
        prevFocusAction.getValue(Action.NAME));
    component.getActionMap().put(prevFocusAction.getValue(Action.NAME), prevFocusAction);
  }
}

class PrevFocusAction extends AbstractAction {
  PrevFocusAction() {
    super("Move Focus Backwards");
  }

  public void actionPerformed(ActionEvent evt) {
    ((Component) evt.getSource()).transferFocusBackward();
  }
}