Here you can find the source of getTitleLineBorderColor()
public static Color getTitleLineBorderColor()
//package com.java2s; import javax.swing.*; import javax.swing.border.Border; import javax.swing.border.LineBorder; import java.awt.*; public class Main { public static Color getTitleLineBorderColor() { Border b = UIManager.getBorder("TitledBorder.border"); if (b instanceof LineBorder) { return ((LineBorder) b).getLineColor(); }/*from w ww. ja v a 2s . c o m*/ return Color.GRAY; } }