Communicator e3000 MPE/iX Release 6.5 Express 2 (Software Release C.65.02) (30216-90322)

Chapter 3 33

Technical Articles

Java Servlets for MPE/iX

Apache 1.3.9 for MPE/iX is currently available as an individual patch from the HP

Response Center. Please refer to the Apache 1.3.9 article in this Communicator for release

and installation information about Apache 1.3.9.

Java Servlets do not work with Apache 1.3.4 since this version lacks the necessary DSO

capability.

System Requirements

Java Servlets running on MPE/iX require the following software and patches:

• MPE/iX 6.0 or 6.5

• Apache 1.3.9 or WebWise Secure Web Server for MPE/iX

• MPELX44 for 6.0 or 6.5 (for DSO capability)

• MPELXC6 for 6.0 or 6.5 (for DSO when Procedure Exits (PEs) are enabled). If the

following error message occurs and MPEXL44 is already installed on your system, you

will also need to install this patch: “An invalid pointer was detected by VIRTUAL

SPACE MANAGEMENT.”

• Current Java release: JDK 1.1.7B, SDK 1.2, or SDK 1.2.2

Any additional requirements for Apache 1.3.9 or WebWise Secure Web Server should be

met before installing and running Java Servlets.

The following are estimates of disk space needs:

• 1 MB for product ﬁles (conﬁguration ﬁles, class libraries, startup/shutdown ﬁles,

example ﬁles)

• 2 MB documentation (API speciﬁcations)

• Additional space for log ﬁles

• Additional space for new servlets

Technical Overview

The Java Servlets product on MPE/iX consists of an add-on module to Apache, called

"mod_jserv," and a standalone Java application, referred to as the "servlet engine" or

JServ. Mod_jserv is implemented as a Dynamic Shared Object (DSO) and the servlet

engine runs on top of the MPE's Java Virtual Machine (JVM). Mod_jserv module and the

servlet engine are open source software from the Java Apache Project, Apache JServ 1.1

The MPE implementation of Java servlets is referred to as a three-tiered model because it

consists of three components. Some implementations of Java servlets are two-tiered with

the servlet engine being part of the web server. The three tiers on MPE/iX are:

1. The web browser

2. The Apache web server with add-on module, mod_jserv.so

3. The servlet engine, JServ