StringBuilder vs String concatenation in toString() in Java

Question

Given the 2 toString() implementations below, which one is preferred:

public String toString(){
    return \"{a:\"+ a + \", b:\" + b + \", c: \"         


        

Answer 1

For simple strings like that I prefer to use

"string".concat("string").concat("string");

In order, I would say the preferred method of constructing a string is using StringBuilder, String#concat(), then the overloaded + operator. StringBuilder is a significant performance increase when working large strings just like using the + operator is a large decrease in performance (exponentially large decrease as the String size increases). The one problem with using .concat() is that it can throw NullPointerExceptions.