static Environment getCurrentEnvironment() {
		return environmentHolder.get();
	}
An {@code ApplicationListener} that will parse command line options and also replace the default boot commandline
{@link PropertySource} with those values. This turns out to be the most elegant solution if we want to keep the
{@link SpringApplicationBuilder} code clean.

@author Eric Bottard
@author Luke Taylor
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/server/options/CommandLinePropertySourceOverridingListener.java