In a windows environment, you can get the computer name from the environment variable with this:
java.lang.System.getenv("COMPUTERNAME");
You can also rely on the DNS to identify the host name of the QIE server with this:
java.net.InetAddress.getLocalHost().getHostName();
There is not currently an API to return the System Configuration -> System Name value. We have entered an enhancement request for this feature. (Bug# 1271)