StringBuilderVsStringConcatenation.java

/**
 * See http://stackoverflow.com/questions/38287661/how-to-get-tostring-for-each-element-of-an-arraylist/38287746?noredirect=1#comment63993889_38287746
 */
public static void main(String[] args) {
	long start = System.currentTimeMillis();

	StringBuilder  sb = new StringBuilder();
	for (int i = 0; i < 100000; i++) {
		sb.append(i);
	}

	long timeWithStringBuilder = System.currentTimeMillis() - start;
	start = System.currentTimeMillis();

	String s = "";
	for (int i = 0; i < 100000; i++) {
		s = s + i;
	}

	long timeWithConcatenation = System.currentTimeMillis() - start;

	System.out.println("With StringBuilder: " + timeWithStringBuilder + " ms\nWith concatenation: " + timeWithConcatenation + " ms");
		
	// Output:
	// With StringBuilder: 67 ms
    // With concatenation: 15665 ms
}