regarding arraycopy() method

[Pratik D mehta]

 public class sample20 {
    int arr1[] = new int[10];
    int arr2[] = new int[10];
public static void main(String args[])
    {
    sample20 s1 = new sample20();
    sample20 s2 = new sample20();

    for(int i =0 ;i<10;i++ )
    {
        s1.arr1[i]=i;
        s1.arr2[i]=i+10;
    }
    System.out.println();
    for(int i =0 ;i<10;i++ )
    {
        System.out.print(s1.arr1[i]);
        
    }
    System.out.println();
    for(int i =0 ;i<10;i++ )
    {
        System.out.print(s1.arr2[i]);

    }
    System.out.println();
    System.arraycopy(s1.arr1,0,s1.arr2,0,10);
    //My question is why cant we write here
    //System.arraycopy(s1.arr1[],0,s1.arr2[],0,10);--why this dosent work
    System.out.println();
    for(int i =0 ;i<10;i++ )
    {
        System.out.print(s1.arr1[i]);

    }
    System.out.println();
    for(int i =0 ;i<10;i++ )
    {
        System.out.print(s1.arr2[i]);

    }
    System.out.println();
}
}   

//My question is why cant we write in code
//System.arraycopy(s1.arr1[],0,s1.arr2[],0,10);--why this dosent work

[Wouter Oet]

Because it is not:
System.arraycopy(s1.arr1[],0,s1.arr2[],0,10);
But
System.arraycopy(s1.arr1,0,s1.arr2,0,10);

[David Newton]

That's kind of a circular answer.

In any case, foo[] isn't a valid expression; it's a type. You can have a *reference* to a foo[], but the reference won't include the brackets. You can refer to a *member* of a foo[], but then you need an index, like foo[0]. So the bottom line is that it's syntactically invalid.

[Pratik D mehta]

Thank you David and Wouter