You can either specify it on command line or within program code by setting three system properties as below:

  1. proxyHost=proxy_host_name
  2. proxyPort=proxy_port
  3. proxySet=true

For example if a proxy is running on localhost at port 8080 then we can use:

java -DproxyHost=localhost -DproxyPort=8080 -DproxySet=true YourProgram

The same properties can be set within your Java program by System.getProperties().put(key, value);

That's it folks!