What is the purpose of the stringbuilder class

Question

Problem:

Question 1- Do the following two methods have the same signature or different signatures?

private int methodA(int x)

public int methodA(int y)

Question 2- Do the following two methods have the same signature or different signatures?

public int methodA(int x, char sym)

public int methodA(int y)

Question 3- What is the term for two or more methods in the same class definition file having the same name but different signatures?

Question 4- What is the purpose of the StringBuilder class?

Question 5- What does immutable mean?

 

Please describe in detail the purpose of the StringBuilder class.