This figure shows how two Java2 Enterprise Edition (J2EE) applications are distributed across three tiers: the client tier on the client machine; the middle tier, which contains the Web tier and the business logic tier on the J2EE server machine; and the enterprise data tier on the database server machine. The two applications are distributed across these tiers as follows:

• J2EE application 1 has three components: an application client on the client tier, Enterprise JavaBeans in the business logic tier on the J2EE server machine, and the database on the enterprise data tier

• J2EE application 2 has four components: dynamic HTML pages on the client tier, JavaServer Pages (JSPs) and servlets on the Web tier that is located on the J2EE server machine, Enterprise JavaBeans in the business logic tier on the J2EE server machine, and the database on the enterprise data tier.