Java system properties

Java™ system properties determine the environment in which you run your Java programs. They are similar to system values or environment variables in IBM® i.

Starting an instance of a Java virtual machine (JVM) sets the values for the system properties that affect that JVM.

You can choose to use the default values for Java system properties or you can specify values for them by using the following methods:

  • Adding parameters to the command line (or the Java Native Interface (JNI) invocation API) when you start the Java program
  • Using the QIBM_JAVA_PROPERTIES_FILE job-level environment variable to point to a specific properties file. For example:
  • Creating a file that you create in your user.home directory
  • Using the /QIBM/userdata/java400/ file

IBM i and the JVM determine the values for Java system properties by using the following order of precedence:

  1. Command line or JNI invocation API
  2. QIBM_JAVA_PROPERTIES_FILE environment variable
  3. user.home file
  4. /QIBM/UserData/Java400/
  5. Default system property values