Why can I add characters to strings but not characters to characters?

Question

So I wanted to add a character to a string, and in some cases wanted to double that characters then add it to a string (i.e. add to it itself first). I tried this as shown b

Answer 1

 String string = X + X;

Here X i'ts threated as a variable

You should use something as

String string ="x x";

Or

String x = "something";
String y = "else";

then String string= x+y; should work just fine, this is because you are concatening with the "+" sign, you could also use

string = string.concat(x+y); 

or

string = string.concat("something"+"else");