System.setProperty("web.proxyHost", "proxy.example.com"); System.setProperty("web.proxyPort", "8080");
System.setProperty("log4j.configurationFile", "log4j2.xml");In this example, the code sets the system property for the configuration file of the log4j logging framework. This allows the framework to use the specified configuration file instead of the default. The java.io System setProperty method is part of the java.lang package library.