Benchmark for appending delimited data to StringBuilder

StringBuilderAppendBench.java

package bench;

public class StringBuilderAppendBench
{
    private static final int ROUNDS = 100;
    private static final int ITERATIONS = 100000;
    
    private static final StringBuilder sb = new StringBuilder(1000000); 
    
    public static void main(String[] args)
    {
        long start;
        long end;
        long diff;
        long total;

        
        // warm-up
        for (int i = 0; i < ITERATIONS; i++)
        {
            appendAfter();
        }
        sb.setLength(0);
        for (int i = 0; i < ITERATIONS; i++)
        {
            appendBefore();
        }
        sb.setLength(0);
        
        // appendAfter
        total = 0;
        for (int r = 1; r <= ROUNDS; r++)
        {
            start = System.currentTimeMillis();
            for (int i = 0; i < ITERATIONS; i++)
            {
                appendAfter();
            }
            end = System.currentTimeMillis();
            diff = end-start;
            total += diff;
            //System.out.printf("appendAfter round %d took %dms\n", r, diff);
            sb.setLength(0);
        }
        System.out.printf("appendAfter average: %dms\n", total / ROUNDS);
        
        // appendBefore
        total = 0;
        for (int r = 1; r <= ROUNDS; r++)
        {
            start = System.currentTimeMillis();
            for (int i = 0; i < ITERATIONS; i++)
            {
                appendBefore();
            }
            end = System.currentTimeMillis();
            diff = end-start;
            total += diff;
            //System.out.printf("appendBefore round %d took %dms\n", r, diff);
            sb.setLength(0);
        }
        System.out.printf("appendBefore average: %dms\n", total / ROUNDS);

        // appendMaybe
        total = 0;
        for (int r = 1; r <= ROUNDS; r++)
        {
            start = System.currentTimeMillis();
            for (int i = 0; i < ITERATIONS; i++)
            {
                appendMaybe();
            }
            end = System.currentTimeMillis();
            diff = end-start;
            total += diff;
            //System.out.printf("appendMaybe round %d took %dms\n", r, diff);
            sb.setLength(0);
        }
        System.out.printf("appendMaybe average: %dms\n", total / ROUNDS);

    }
    
    static void appendAfter()
    {
        sb.append('{');
        for (int i = 0; i < 10; i++)
        {
            sb.append('"');
            sb.append(i);
            sb.append('"');
            sb.append(':');
            sb.append(i);
            sb.append(',');
        }
        sb.setLength(sb.length() - 1);
        sb.append('}');
    }
    
    static void appendBefore()
    {
        sb.append('{');
        String delimiter = "";
        for (int i = 0; i < 10; i++)
        {
            sb.append(delimiter);
            sb.append('"');
            sb.append(i);
            sb.append('"');
            sb.append(':');
            sb.append(i);
            delimiter = ",";
        }
        sb.append('}');
    }
    
    static void appendMaybe()
    {
        sb.append('{');
        for (int i = 0; i < 10; i++)
        {
            sb.append('"');
            sb.append(i);
            sb.append('"');
            sb.append(':');
            sb.append(i);
            if (i < 9)
            sb.append(',');
        }
        sb.append('}');
    }
}