Chapter 5. Performance tuning 131
In this example, we completed the following tasks:
1. The command line arguments were copied to one Notepad session and the parameter
name –classpath and a space were added at the end.
2. A file with a list of the JAR files was created and opened in another Notepad session.
3. The qualification was added to the beginning of the first line and the colon was added to
the end.
The lines that follow should be amended in the same way (no colon on the last), the lines
joined into one long line with no spaces, and then copied to the clipboard. Finally the long
string should be pasted into the other session after –classpath.
An alternative technique is not to run the CRTJVAPGM command, but to add the following
line to the command line arguments:
-Dos400.optimization=40
This sets the default optimization level to 40. If there are no attached Java programs, then
they are created the next time the application is started. This technique means that the next
application start will be slow, possibly so slow that it times out. But if the Java programs are
created, then it confirms that your configuration was correct and they will be used.
You can verify whether the Java programs exist by using the DSPJVAPGM command. If the
programs exist and you want to use this technique, then delete them by using the Delete Java
Program (DLTJVAPGM) command. Note that this command does not delete the Java class
file, but the hidden statically compiled program associated with it.
Enterprise bean settings
Similar to connections, beans are pooled. The default minimum pool size is 2, and the
maximum is 100. Unless you have an extremely large installation, these values should work.
Even if you had hundreds of clients, you would need more than 100 beans only if they were all
active and more than 100 were frequently using the same bean at the same time.
However, on a moderately busy system, you may improve performance by increasing the
minimum pool size and possibly by reducing the maximum. Ideally you would watch usage by
using the Resource Analyzer.
These settings are controlled on the Advanced page of a bean’s settings as shown in
Figure 5-23.
