add elements from one array to "empty array"

Use System.arrayCopy to copy arrays. Example:

System.arraycopy(newarray, 0, result, 0, newarray.length)

The first argument is the source array, then the source position, then the destination array and destination position, and the length.

        int[] newarray = new int[] {1,2,3,4}  
        int[] result = new int[newarray.length];
        for(int i=0;i<newarray.length;i++)
            result[i]=newarray[i];

Lets say you want to assign the third value in newarray to the third index in result. That would be like:

result[2] = newarray[2]

System.arraycopy(newarray, 0, result, 0, newarray.length);

or you can do it manually

for(int i = 0; i < newarray.length; i++) {
    result[i] = newarray[i];
}

to work with Arrays, you can use

Arrays.asList(Object[] a);

Either copy elements one at a time in a loop or use System.arraycopy.

Understand that an array in Java is like an array in C in that it's fixed length (there are other classes like ArrayList for variable-length use). So you don't "add" a new element, you simply assign a value (x[i] = something;) to an existing element (which was initialized to zero when the array was created).

To my knowledge there's no "add all elements of this array" method on ArrayList, so to do that you'd have to loop through the array and add the elements one at a time. There are methods to go the other direction.

This should also work:

Arrays.asList(result).addAll(Arrays.asList(newarray));

Returns a fixed-size list backed by the specified array. (Changes to the returned list "write through" to the array.)

Using static imports:

asList(result).addAll(asList(newarray));