Setting environment variable from code in Java

Normally the environment variables are set, as the name implies, but the environment. However, sometimes a code runs as part of some environment that you cannot control.
Many times it happens as part of integration or performance tests.

And here's the way to overcome it:

	void setEnv(String name, String value) {
	try {
	final Class<?> envClass = Class.forName("java.lang.ProcessEnvironment");
	final Class<?> uMapClass = Class.forName("java.util.Collections$UnmodifiableMap");
	final Field mField = uMapClass.getDeclaredField("m");
	mField.setAccessible(true);
	final Field theUnmodifiableEnvironment = envClass.getDeclaredField("theUnmodifiableEnvironment");
	theUnmodifiableEnvironment.setAccessible(true);
	final Map oldMap = (Map) theUnmodifiableEnvironment.get(System.getenv());
	final HashMap newMap = new HashMap(oldMap);
	newMap.put(name, value);
	mField.set(System.getenv(), newMap);
	} catch (Exception e) {
	e.printStackTrace();
	}
	}

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