Use StringBuilder for concatenation of strings in loops

Medium

---

JavaClean codecsharp

Avoid using the + operator to concatenate strings in loops. StringBuilder implies that we are building a string. That improves the code readability.

Examples

Example 1:

Positive

Correct implementation following the practice.

package org.main;

import java.util.ArrayList;
import java.util.List;

public class Main {

	public static void main(String[] args) {
		List<String> items = new ArrayList();
		
		StringBuilder sb = new StringBuilder();
		for (String item : items) {
		    sb.append(item);
		}
		String result = sb.toString();

	}

Negative

Incorrect implementation that violates the practice.

package org.example;

import java.util.ArrayList;
import java.util.List;

//TIP To <b>Run</b> code, press <shortcut actionId="Run"/> or
// click the <icon src="AllIcons.Actions.Execute"/> icon in the gutter.
public class Main {

    private void ListInitialisation() {
        ArrayList<Integer> list = new ArrayList<>(100);
    }

    public void concat() {
        List<String> items = new ArrayList<>();

        String result = "";
        for (String item : items) {
            result = result + item;
        }
    }

}