7, Value Stack

1. About the value stack:

1). HelloWorld, ${productname} reads the ProductName value, which is not actually in the request and other domain objects, but is obtained from the value stack.

2). Valuestack:

I. The value stack object can be obtained from the Actioncontext
II. Value stack divided into two logical parts

> Map stack: Actually a ognlcontext type, a map, and a reference to Actioncontext. There are various maps in the store:
Requestmap, Sessionmap, Applicationmap, Parametersmap, attr

> Object stack: Is actually a compoundroot type and is a stack defined using ArrayList. It holds various objects related to the current Action instance.
is a stack of data structure meaning.

7, Value Stack