How can i programm a text(String) changer?

Question

I mean like when a=c b=g
String text = "abababa";
System.out.println(text);

Output: cgcgcgc

How can i programm it which satatement do i need?

Sry for my bad english...

Answer 1

String text = "abababa";
String result = text.replace('a', 'c');
System.out.println(result);

output: cbcbcbc