Two array objects compareTo:

Question

Have two arrays: ttt and ppp. I have to have a method to compare them.
public int compareTo(object ob)
both of the arrays are int type and both have super long numbers in them.
Thanks

Answer 1

Actually, the reflection api is pretty fast since
JDK1.4.0...No. Reflection could not be fast. In J2SDK1.4 it seems to be faster then in previous releases. But improvments do not include array operations. So here are some results of simple benchmark:
bash-2.05a$ /usr/java/jdk1.3.1_04/bin/java TestArray
Result for reflect copiing (3 elements, 1000000 times): 4915ms
Result for system copiing (3 elements, 1000000 times): 460ms
Result for pure java copiing (3 elements, 1000000 times): 137ms
bash-2.05a$
bash-2.05a$ /usr/java/j2sdk1.4.0_01/bin/java TestArray
Result for reflect copiing (3 elements, 1000000 times): 6082ms
Result for system copiing (3 elements, 1000000 times): 491ms
Result for pure java copiing (3 elements, 1000000 times): 115ms
bash-2.05a$
bash-2.05a$ /usr/java/j2sdk1.4.1/bin/java TestArray
Result for reflect copiing (3 elements, 1000000 times): 5738ms
Result for system copiing (3 elements, 1000000 times): 497ms
Result for pure java copiing (3 elements, 1000000 times): 157ms
bash-2.05a$
As you can see, in new Java reflect operations on arrays are even slower then in jdk1.3.1. System copiing is good alternative for pure java (element by element) copiing, espetially for big arrays. And here is the code of this benchmark, test it on your PC also:
import java.lang.reflect.*;
public class TestArray {
    static void doNothing(){}
    static int field;
    public static void main(String[] args) throws Exception {
        final int COUNT = 3, TIMES = 1000*1000;
        final String[] arr1 = new String[COUNT];
        final String[] arr2 = new String[COUNT];
            long time = -System.currentTimeMillis();
            for(int i=TIMES; i-->0;)
                copyReflect(arr1, arr2, COUNT);
            time += System.currentTimeMillis();
            System.out.println("Result for reflect copiing ("+COUNT+" elements, "+TIMES+" times): "+time+"ms");
            long time = -System.currentTimeMillis();
            for(int i=TIMES; i-->0;)
                copySystem(arr1, arr2, COUNT);
            time += System.currentTimeMillis();
            System.out.println("Result for system copiing ("+COUNT+" elements, "+TIMES+" times): "+time+"ms");
            long time = -System.currentTimeMillis();
            for(int i=TIMES; i-->0;)
                copyPureJava(arr1, arr2, COUNT);
            time += System.currentTimeMillis();
            System.out.println("Result for pure java copiing ("+COUNT+" elements, "+TIMES+" times): "+time+"ms");
    private static void copyReflect(Object src, Object dst, int count) {
        for(int i=count; i-->0; ) Array.set(dst, i, Array.get(src, i));
    private static void copySystem(Object src, Object dst, int count) {
        System.arraycopy(src, 0, dst, 0, count);
    private static void copyPureJava(String[] src, String[] dst, int count) {
        for(int i=count; i-->0; ) dst[i] = src;