Date: 2016jun6 Update: 2025sep18 Language: Java Keywords: HashMap, TreeMap Q. Java: Make a case-insensitive HashSet A. Use TreeSet as shown in this full example:

import java.util.TreeSet; class Demo { public static void main(String []args) { TreeSet<String> myset = new TreeSet<String>(String.CASE_INSENSITIVE_ORDER); myset.add("apple"); myset.add("banana"); myset.add("Apple"); myset.add("aPPle"); System.out.println("myset=" + myset); } }

Output:

myset=[apple, banana]