Passing arrays as function parameter in java

1. Assigning objects to the array of reference before the calling of function:

public static void main(String[] args) {
  byte[] arr=new byte[3];
byte[] x=     calc(arr);
// in this case x = arr ( not null);
    }

    public byte[] calc (byte[] arr)
    {
        //do something here.
        return arr;
       
    }

2. Assigning objects to the array of references in the called of function:

public static void main(String[] args) {
  byte[] arr=null;
byte[] x=     calc(arr);
// in this case x = null
    }

    public byte[] calc (byte[] arr)
    {
arr = new byte[3];
        //do something here.
        return arr;
       
    }