Here you can find the source of isSet(Attributes attributes, String name)
private static boolean isSet(Attributes attributes, String name)
//package com.java2s; import java.util.jar.Attributes; public class Main { private static boolean isSet(Attributes attributes, String name) { boolean isSet = false; String s = attributes.getValue(name); if (s != null) { s = s.trim();//from w w w. j a v a 2 s. c o m isSet = s.equalsIgnoreCase("true"); } return isSet; } }