System properties

You can specify system properties to configure various aspects of the IBM Toolbox for Java. For example, you can use system properties to define a proxy server or a level of tracing. System properties are useful for convenient runtime configuration without needing to recompile code. System properties work like environment variables in that when you change a system property during runtime, the change is generally not reflected until the next time you run the application.

There are several ways that you can set system properties:

• Using the java.lang.System.setProperties() method

  You can set system properties programmatically by using the java.lang.System.setProperties() method.

  For example, the following code sets the com.ibm.as400.access.AS400.proxyServer property to hqoffice:

  Properties systemProperties = System.getProperties();
     systemProperties.put ("com.ibm.as400.access.AS400.proxyServer", "hqoffice");
     System.setProperties (systemProperties);

• Using the -D option of the java command

  Many environments allow you to set system properties when running applications from a command line by using the -D option of the java command.

  For example, the following program runs the application called Inventory with the com.ibm.as400.access.AS400.proxyServer property set to hqoffice:

     java -Dcom.ibm.as400.access.AS400.proxyServer=hqoffice Inventory

• Using a jt400.properties file

  In some environments, it may be inconvenient to instruct all users to set their own system properties. As an alternative, you can specify IBM Toolbox for Java system properties in a file called jt400.properties that is searched for as if it is part of the com.ibm.as400.access package. In other words, place the jt400.properties file in a com/ibm/as400/access directory pointed to by the classpath.

  For example, set the com.ibm.as400.access.AS400.proxyServer property to hqoffice by inserting the following line into the jt400.properties file:

     com.ibm.as400.access.AS400.proxyServer=hqoffice

  The backslash character (\) functions as an escape character in properties files. Specify a literal backslash character by using two backslashes (\\).

  Modify this sample of a jt400.properties file for your environment.

• Using a Properties class

  Some browsers do not load properties files without explicitly changing security settings. However, most browsers do allow properties in .class files, so IBM Toolbox for Java system properties can also be specified by a class called com.ibm.as400.access.Properties which extends java.util.Properties.

  For example, to set the com.ibm.as400.access.AS400.proxyServer property to hqoffice, use the following Java code:

     package com.ibm.as400.access;
  
     public class Properties
     extends java.util.Properties
     {
        public Properties ()
        {
           put ("com.ibm.as400.access.AS400.proxyServer", "hqoffice");
        }
     }

  Modify and compile this sample of a Properties.java source file for your environment.

If an IBM Toolbox for Java system property is set using more than one of the mechanisms described above, then the precedence is as follows (in order of decreasing precedence):

1. The system property set programmatically using java.lang.System.setProperties()
2. The system property set using the -D option of the java command
3. The system property set using a Properties class
4. The system property set using a jt400.properties file

IBM Toolbox for Java supports the following system properties:

• Proxy server properties
• Trace properties
• CommandCall/ProgramCall properties

Proxy server properties

   hostName:portNumber

Trace properties

CommandCall/ProgramCall properties