package java0904_api; class StringTest { private char[] arr; public StringTest() { } public StringTest(char[] arr) { this.arr = arr; } public int length() { return arr.length; } public char charAt(int index) { return arr[index]; } } public class Java115_String { public static void main(String[] args) { StringTest st = new StringTest(new char[] { 'j', 'a', 'v', 'a' }); System.out.println(st.length()); // 4 System.out.println(st.charAt(2)); // v } }