Here you can find the source of setPreferredWidth(JComponent component, int width)
public static void setPreferredWidth(JComponent component, int width)
//package com.java2s; /*//from w ww .j a v a 2 s. co m * Copyright 2016 The Bazel Authors. All rights reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.awt.Dimension; import javax.swing.JComponent; public class Main { public static void setPreferredWidth(JComponent component, int width) { int height = component.getPreferredSize().height; component.setPreferredSize(new Dimension(width, height)); } }