Chapter 10, Problem 10.22PE

(Implement the String class) The String class is provided in the Java library. Provide your own implementation for the following methods (name the new class MyString1):

public MyString1(char[] chars):

public char charAt(int index);

public int length();

public MyString1 substring(int begin, int end);

public MyString1 toLowerCase();

public boolean equals(MyString1 s);

public static MyString1 valueOf(int i);