The following JAVA code is to revise the “GenericStack” class which implements array rather than an “ArrayList”.

Program:

//Class definition

class GenericStack<E>

{

/*Declaration of variables*/

public final static int INITIAL_SIZE = 16;

private E[] elements;

private int N;

/*Construct a stack with the default initial capacity */

public GenericStack()

{

//Assign initial size

this(INITIAL_SIZE);

}

/*Construct a stack with the specified initial capacity */

public GenericStack(int initialCapacity)

{

//Assign size

elements = (E[])new Object[initialCapacity];

}

/*Push a new element into the top of the stack */

public E push(E o)

{

//Condition

if (N >= elements.length)

{

//Assign array size into variable "t"

E[] t = (E[])new Object[elements.length * 2];

//Copy array elements

System.arraycopy(elements, 0, t, 0, elements.length);

//Assign "t" into "elements"

elements = t;

}

//Return statement

return elements[N++] = o;

}

/*Return and remove the top element from the stack*/

public E pop()

{

//Return statement

return elements[--N];

}

/*Return the top element from the stack */

public E peek()

{

//Return statement

return elements[N - 1];

}

/*Function definition to check empty*/

public boolean isEmpty()

{

//Return statement

return N == 0;

}

/*Return the number of elements in the stack */

public int getSize()

{

//Return statement

return N;

}

//Main method

public static void main(String[] args)

{

//Assign object to "GenericStack"

GenericStack<String> obj = new GenericStack<>();

//Push elements into stack

obj.push("London");

obj.push("Paris");

obj.push("Berlin");

//Print elements

System.out.print("Stack 1: ");

//Loop

while (!obj.isEmpty())

{

//Print statement

System.out.print(obj.pop() + " ");

}

//Print statement

System.out.println("\n");

}

}

Stack 1: Berlin Paris London