# Understanding the n-Tiered Business Components Architecture

By using the Business Components for Java design-time wizards and editors, you can build business logic tiers by defining the characteristics of components: their attributes, relationships, and business rules. Business Components for Java generates Java source code and XML metadata to implement the behavior you have specified. Because the code inherits from a framework, the Java source files are concise and do not contain large amounts of generated code, so it's easy to see where to add the code that models your business. You can use JDeveloper to add the Java code to enhance or change the behavior, and easily test the application services, independently of the deployment platform.

Business Components for Java then helps you deploy application modules (without modification) to an Oracle 8i JServer environment as Oracle 8i CORBA server objects (physical two-tier), Visibroker CORBA server objects (physical three-tier), OAS EJB session beans (physical three-tier), or Oracle 8i EJB session beans (physical two-tier), or in local mode (physical two-tier).

The following table shows the deployment configurations you can choose. There are three possible physical tiers: the client process, the application server process, and the database process. The database process is always present to manage the application data.

Type of Client | Process Running Client | Type of Business Components Deployment | Process Running Business Components | Number of Physical Tiers
Java Application or Applet | Client Process | Local Mode | Client Process | 2
Java Application or Applet | Client Process | VisiBroker CORBA Server Object | Application Server Process | 3
Java Application or Applet | Client Process | Oracle8i CORBA Server Object | Database Process | 2
Java Application or Applet | Client Process | Oracle8i EJB | Database Process | 2
Java Application or Applet | Client Process | EJB in Application Server | Application Server Process | 3
JSP, XSQL page, or Servlet | Application Server Process | Local Mode | Application Server Process | 2
JSP, XSQL page, or Servlet | Application Server Process | VisiBroker CORBA Server Object | Different Application Server Process | 3
JSP, XSQL page, or Servlet | Application Server Process | Oracle8i CORBA Server Object | Database Process | 2
JSP, XSQL page, or Servlet | Application Server Process | Oracle8i EJB | Database Process | 2
JSP, XSQL page, or Servlet | Application Server Process | EJB in Application Server | Same or Different Application Server Process | 2 or 3
Java Stored Procedure | Database Process | Local Mode | Database Process | 1