please use java and provide code. Dont copy wrong answers.

you can use charAt method

The StringBuilder class is provided in the Java library. Provide your own implementation (name the new class MyStringBuilder2) with three data fields, array of characters, size, capacity, and the following methods: public MyStringBuilder2(String s); constructor (1 points) public MyStringBuilder2 append(MyStringBuilder2 s); a method that takes s object and add s array of characters to this array of characters, then returns this. (3 points) public MyStringBuilder2 substring(int begin, int end); (3 points) Accessors methods that return the size, the capacity, and the array of characters as a string. (3 points) Do not use any method from String (you can use length), StringBuilder, or StringBuffer