SQL/MX Guide to Stored Procedures in Java (G06.24+, H06.03+)

Introduction
HP NonStop SQL/MX Guide to Stored Procedures in Java—523727-004
1-12
The SPJ Environment
The SPJ Environment
NonStop SQL/MX processes CALL statements in an SPJ environment, which is hosted
within an SQL/MX UDR server process. The SPJ environment includes an embedded
JVM inside of which SPJ methods, invoked by CALL statements, execute, as shown in
Figure 1-4.
This subsection explains some of the ways in which the SPJ environment in NonStop
SQL/MX differs from a typical Java environment:
•
SQL/MX UDR Server Process on page 1-12
•
Multithreading in an SPJ Environment on page 1-15
•
Class Loaders in an SPJ Environment on page 1-15
•
Application Classes That an SPJ Can Access on page 1-17
•
Maintaining Class and JAR Files in an SPJ Environment on page 1-18
SQL/MX UDR Server Process
The SQL/MX UDR server is a program executable named MXUDR in
$SYSTEM.SYSTEM. When NonStop SQL/MX processes the first CALL statement of an
application, it starts an SQL/MX UDR server process. An SQL/MX UDR server process
hosts one SPJ environment and services one or more CALL statements of an SQL/MX
application during its execution. When an application terminates, its SQL/MX UDR
server processes also terminate.
Figure 1-4. SPJ Environment in NonStop SQL/MX
VST004.vsd
Application
NonStop
SQL/MX
CALL...
NonStop Server for Java
SQL/MX Language Manager
NonStop SQL/MX
JDBC/MX (C++)
Class File
Payroll.class
Java Method
SQL/MX UDR Server Process
JVM
JDBC/MX (Java)