How can we dynamically allocate and grow an array

Question

I am working on a project, but I cannot use any existing java data structures (ie, ArraysList, trees, etc)

I can only use arrays. Therefore, I need to dynamically up

Answer 1

Take a look at implementation of Java ArrayList. Java ArrayList internally uses a fixed size array and reallocates the array once number of elements exceed current size. You can also implement on similar lines.