public void doLayout() {
   super.doLayout();
   if (getScrollbarDisplayPolicy() == SCROLLBARS_NEVER) {
     // Use this class's calculateChildSize() and re-do layout of child
     Component c = getComponent(0);
     Dimension cs = calculateChildSize();
     Insets i = getInsets();
     c.setBounds(i.left, i.top, cs.width, cs.height);
   }
 }
  /**
   * Determine the size to allocate the child component. Overrides calculateChildSize() in
   * ScollPane. If the viewport area is bigger than the child's preferred size then the child is
   * allocated enough to fill the viewport, otherwise the child is given its preferred size. Calls
   * super.calculateChildSize(). If scrolling is disabled, the child is allocated enough to fill the
   * viewport.
   */
  Dimension calculateChildSize() {
    // Calculate the view size, accounting for border but not scrollbars
    // - don't use right/bottom insets since they vary depending
    //   on whether or not scrollbars were displayed on last resize.
    Dimension size = getSize();
    Insets insets = getInsets();
    int viewWidth = size.width - insets.left * 2;
    int viewHeight = size.height - insets.top * 2;

    // Determine whether or not horz or vert scrollbars will be displayed.
    boolean vbarOn;
    boolean hbarOn;
    Component child = getComponent(0);
    Dimension childSize = new Dimension(child.getPreferredSize());

    if (getScrollbarDisplayPolicy() == SCROLLBARS_AS_NEEDED) {
      vbarOn = childSize.height > viewHeight;
      hbarOn = childSize.width > viewWidth;
    } else if (getScrollbarDisplayPolicy() == SCROLLBARS_ALWAYS) {
      vbarOn = hbarOn = true;
    } else { // SCROLLBARS_NEVER
      vbarOn = hbarOn = false;
    }

    // Adjust predicted view size to account for scrollbars.
    int vbarWidth = getVScrollbarWidth();
    int hbarHeight = getHScrollbarHeight();
    if (vbarOn) {
      viewWidth -= vbarWidth;
    }
    if (hbarOn) {
      viewHeight -= hbarHeight;
    }

    // If child is smaller than view, size it up.
    if ((childSize.width < viewWidth) || (getScrollbarDisplayPolicy() == SCROLLBARS_NEVER)) {
      childSize.width = viewWidth;
    }
    if ((childSize.height < viewHeight) || (getScrollbarDisplayPolicy() == SCROLLBARS_NEVER)) {
      childSize.height = viewHeight;
    }

    return childSize;
  }