Compare three ways to clear a String in java, Java

Language: Layout:

//Title of this code
//'main' method must be in a class 'Rextester'.

import java.util.*;
import java.lang.*;

class Rextester
{  
    static HashMap<String, String> brandPriceDates = new HashMap<String, String>();
    static String a;
    public static void main(String args[])
    {       
        System.out.println("Three ways to clear a string...");
        
        long time = System.currentTimeMillis();
        StringBuilder sb = new StringBuilder();
        for( int i = 0; i < 10000000; i++ ) {
            sb.delete( 0, sb.length() );
            sb.append( "someString" );
            sb.append( "someString2" );
            sb.append( "someStrin4g" );
            sb.append( "someStr5ing" );
            sb.append( "someSt7ring" );
            a = sb.toString();
        }
        System.out.println( "using delete: " + Long.toString(System.currentTimeMillis()-time));
        time = System.currentTimeMillis();
        for( int i = 0; i < 10000000; i++ ) {
            StringBuilder sb2 = new StringBuilder();
            sb2.append( "someString" );
            sb2.append( "someString2" );
            sb2.append( "someStrin4g" );
            sb2.append( "someStr5ing" );
            sb2.append( "someSt7ring" );
            a = sb2.toString();
        }
        System.out.println( "using new: " + Long.toString(System.currentTimeMillis()-time));
        
        time = System.currentTimeMillis();
        sb = new StringBuilder();
        for( int i = 0; i < 10000000; i++ ) {
            sb.setLength(0);
            sb.append( "someString" );
            sb.append( "someString2" );
            sb.append( "someStrin4g" );
            sb.append( "someStr5ing" );
            sb.append( "someSt7ring" );
            a = sb.toString();
        }
        System.out.println( "using setLength: " + Long.toString(System.currentTimeMillis()-time));
    }
}

[ + ] Show input
Compilation time: 0.71 sec, absolute running time: 2.94 sec, cpu time: 2.9 sec, memory peak: 103 Mb, absolute service time: 3.66 sec