Here you can find the source of addBorder(JComponent component, Border border)
public static void addBorder(JComponent component, Border border)
//package com.java2s; /*//from w w w . j ava 2 s . c o m * Copyright 2000-2013 JetBrains s.r.o. * * 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 javax.swing.*; import javax.swing.border.Border; import javax.swing.border.CompoundBorder; public class Main { public static void addBorder(JComponent component, Border border) { if (component == null) return; if (component.getBorder() != null) { component.setBorder(new CompoundBorder(border, component.getBorder())); } else { component.setBorder(border); } } }