public static boolean checkRequestedVersion(String rv) {
		if (!isRequestedVersion(rv)) {
			throw new IllegalArgumentException(
					"Invalid JAVA version, should be a number optionally followed by a plus sign");
		}
		return true;
	}
Returns the Path to JAVA_HOME

@return A Path pointing to JAVA_HOME or null if it isn't defined
src/main/java/dev/jbang/util/JavaUtil.java