J2SE Version (please include all output from java -version flag):
java version "1.6.0_13"
Java(TM) SE Runtime Environment (build 1.6.0_13-b03)
Java HotSpot(TM) Client VM (build 11.3-b02, mixed mode, sharing)

Does this problem occur on J2SE 5.0.x or 6.0? Yes / No (pick one)
Yes

Operating System Configuration Information (be specific):
Client: Microsoft Windows XP [Version 5.1.2600]

Bug Description:
BoxLayout does not attempt to make all components as wide as the widest
component
.
The JavaDoc for BoxLayout says: 'BoxLayout attempts to make all
components in the
column as wide as the widest component.'

What the implementation is actually doing is attempting to make all
components in the column as wide as the container.
Either the JavaDoc should be changed or the implementation should be fixed.

Expected: The 2 buttons to be 200 wide (the width of the widest button)
Actual: The 2 buttons are as wide as the container

import static java.lang.Integer.*;
import static javax.swing.BoxLayout.*;
import static javax.swing.JFrame.*;
import java.awt.*;
import javax.swing.*;

public class Test {
  public static void main(String[] args) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
    frame.setLayout(new BoxLayout(frame.getContentPane(), Y_AXIS));
    frame.add(new JButton("Test") {
      public Dimension getPreferredSize() {
        return new Dimension(200, 50);
      }

      public Dimension getMaximumSize() {
        return new Dimension(MAX_VALUE, MAX_VALUE);
      }
    });
    frame.add(new JButton("Test") {
      public Dimension getPreferredSize() {
        return new Dimension(100, 50);
      }

      public Dimension getMaximumSize() {
        return new Dimension(MAX_VALUE, MAX_VALUE);
      }
    });
    frame.setSize(500, 500);
    frame.setVisible(true);
  }
}