为什么在初始化数组后我无法在数组中分配一些值？

Question

This is my code, after initialized the array, I cannot able to reassign some value in array. It shows array index out of bound exception.

public class NewClass {
    public static void main(String args[]){

        String cl[]={};
        cl[0]="10";      
        System.out.print(cl.length);        
    }    
}

my output:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
    at NewClass.main(NewClass.java:15)
Java Result: 1

Answer 1

String cl[]={};

Creates an instance of an empty array, so you can't add any elements to it.

In order to create a non empty array, use either

String cl[] = {"something",...};

or

String cl[] = new String[theArrayLength];

Answer 2

If you want to declare your array, you can do something like this:

String cl[];

After that you can initialize your array by calling this:

cl = new String[10];

And your System.out.print(cl.length); will return what you want.