Refer to the UML below to implement the data structure of a stack

Step $1$: Create a java interface, StackInterface, to define Stack ADT. $($if there is already the

interface, you do not have to create and use the existing one$)$

Step $2$: Create a java class, LLNode, to represent a node structure.

Step $3$: Create a java class, LinkedStack, to implement the interface above

Step $4$: Create a java class, TestLinkedStack, to test if your implementation works or not

$(1)$ The code of StackInterface:

$(2)$ The code of LLNode:

$(3)$ The code of LinkedStack:

needing to see the codes for each three classes and the final output in TestLinkedStack main method. please help