jetbrick-commons/src/main/java/jetbrick/collections/ArrayStack.java
public T push(T element) {
        int i;
        Object[] els;
        if ((i = size++) >= (els = elements).length) {
            System.arraycopy(els, 0, els = elements = new Object[i << 1], 0, i);
        }
        els[i] = element;
        return element;
    }
public T push(T element) {
        int i;
        Object[] els;
        if ((i = size++) >= (els = elements).length) {
            System.arraycopy(els, 0, els = elements = new Object[i << 1], 0, i);
        }
        els[i] = element;
        return element;
    }
Pushes an item onto the top of this stack.

@param element － the element to be pushed onto this stack
@return the item argument