As a parameter to the JVM command line

As a parameter to the JVM command line System propertiessetting on command line

You can set system-wide properties as parameters to the JVM command line when starting up the application or framework in which is embedded.

IBM Application Developer Kits
With the IBM® SDK, you set JVM system properties by using a -D flag on the Java command line. For example: java -Dderby.system.home=C:\home\\ -Dderby.storage.pageSize=8192 JDBCTest

For other JVMs, see the JVM-specific documentation on setting system properties.