Really old class to test String performance in Java. Wasn't that helpful.

StringPerformance.java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.StringTokenizer;
import java.util.regex.Pattern;

/**
 * Class: StringPerformance
 */
public class StringPerformance {

    public static void main(String args[]) {
        StringBuilder sb = new StringBuilder();
        for (int i = 100000; i < 100000 + 60; i++) {
            sb.append(i).

                    append(' ');
        }

        String sample = sb.toString();

        int runs = 100000;
        for (int i = 0; i < 5; i++)

        {
            {
                long start = System.nanoTime();
                for (int r = 0; r < runs; r++) {
                    StringTokenizer st = new StringTokenizer(sample);
                    List<String> list = new ArrayList<String>();
                    while (st.hasMoreTokens()) {
                        list.add(st.nextToken());
                    }
                }
                long time = System.nanoTime() - start;
                System.out.printf("StringTokenizer took an average of %.1f us%n", time / runs / 1000.0);
            }
            {
                long start = System.nanoTime();
                Pattern spacePattern = Pattern.compile(" ");
                for (int r = 0; r < runs; r++) {
                    List<String> list = Arrays.asList(spacePattern.split(sample, 0));
                }
                long time = System.nanoTime() - start;
                System.out.printf("Pattern.split took an average of %.1f us%n", time / runs / 1000.0);
            }
            {
                long start = System.nanoTime();
                for (int r = 0; r < runs; r++) {
                    List<String> list = new ArrayList<String>();
                    int pos = 0, end;
                    while ((end = sample.indexOf(' ', pos)) >= 0) {
                        list.add(sample.substring(pos, end));
                        pos = end + 1;
                    }
                }
                long time = System.nanoTime() - start;
                System.out.printf("indexOf loop took an average of %.1f us%n", time / runs / 1000.0);
            }
        }

        runs = 10000000;
        long totalTime = 0;
        for (int i = 0; i < runs; i++) {
            String val = "" + Math.random();
            long start = System.nanoTime();
            float f = Float.parseFloat(val);
            long end = System.nanoTime();
            //System.err.println(f);
            totalTime += (end - start);
        }
        long time = totalTime / runs;
        totalTime = 0;
        for (int i = 0; i < runs; i++) {
            String val = "" + Math.random();
            long start = System.nanoTime();
            double d = Double.parseDouble(val);
            long end = System.nanoTime();
            //System.err.println(d);
            totalTime += (end - start);
        }
        long time2 = totalTime / runs;
        System.out.println("Average Float.parseFloat() time was " + time + " ns.");
        System.out.println("Average Double.parseDouble() time was " + time2 + " ns.");
    }
}