append values dynamically into an long[] array

Question

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

Answer 1

long[] s = new long[] {0, 1, 2};
long[] s2=new long[]{3, 4, 5};
int len_s= s.length;
s= Arrays.copyOf(s, len_s+s2.length); //extends range arrays 
System.arraycopy(s2,0,s1,len_s,s2.length); // copy three elements from s2 to s begin at s[len_s]; s2.length is number of elements s2.
System.out.println(Arrays.toString(a1));

output is

[0,1,2,3,4,5]