i need some help regarding adding values into an array

for example

```
long[] s = new long[] {0, 1, 2};

```

when i do this i instantiate an array with the values

but how do i append to this to the above array if i have another value of

```
3, 4, 5

```

to make it like this

```
s = new long[] {1, 2, 3, 4, 5, 6};

```

i tried the System.arraycopy function but i am only able to overide the array and when i try to append to it, i get a null pointer exception

Thanks

**SOLUTION**

i used this with a for loop to put in the values once by one

```
        long[] tmp = new long[a.length + x.length];
    System.arraycopy(a, 0, tmp, 0, a.length);
    System.arraycopy(x, 0, tmp, a.length, x.length);
    a=tmp;

```