You can use System.arraycopy().
int[] source = new int[1000];
int[] part1 = new int[500];
int[] part2 = new int[500];
// (src , src-offset , dest , offset, count)
System.arraycopy(source, 0 , part1, 0 , part1.length);
System.arraycopy(source, part1.length, part2, 0 , part2.length);