stupid int parse test -> stupid int parsing almost twice as fast as the one from the JDK (1.6) Total time: 2.5252283s Avg time: 25.252283ns Total time: 4.094798s Avg time: 40.94798ns

gistfile1.java

import org.junit.Test;

public class IntParseTest {

    private static int parseInt(String s) {
        int result = 0;
        char x;
        boolean negative = false;
        for (int i = 0; i < s.length(); i++) {
            x = s.charAt(i);
            switch (x) {
                case '1':
                case '2':
                case '3':
                case '4':
                case '5':
                case '6':
                case '7':
                case '8':
                case '9':
                case '0':
                    result = result * 10 + (x - 48);
                    break;
                case '-':
                    negative = true;
                    break;
                default:
                    throw new NumberFormatException(s);
            }
        }
        if (negative) {
            return -1 * result;
        } else {
            return result;
        }
    }

    @Test
    public void test() {
        int actual = 0;
        int iterations = 100000000;
        String input = "-122312345";
        long start = System.nanoTime();
        for (int i = 0; i < iterations; i++) {
            actual = parseInt(input);
        }
        long duration = System.nanoTime() - start;
        System.out.println("Total time: " + (duration / (1000 * 1000 * 1000f)) + "s");
        System.out.println("Avg time: " + (duration * 1f / iterations) + "ns");

        start = System.nanoTime();
        for (int i = 0; i < iterations; i++) {
            actual = Integer.parseInt(input);
        }
        duration = System.nanoTime() - start;
        System.out.println("Total time: " + (duration / (1000 * 1000 * 1000f)) + "s");
        System.out.println("Avg time: " + (duration * 1f / iterations) + "ns");

    }
}

Doesn't deal well with invalid inputs that consist of legal characters, though. e.g. 145-5721-5