src/main/java/org/eiichiro/reverb/system/Environment.java
public static String getProperty(String key, String def) {
		return System.getProperty(key, def);
	}
public static String getProperty(String key, String def) {
		return System.getProperty(key, def);
	}
Returns the Java system property corresponding to the specified key (If
the system property doesn't exist, this method returns the specified
default value).

@param key The key of Java system property.
@param def The default value that is returned if the system property
doesn't exist.
@return The Java system property related to the specified key as
{@code String}. If the Java system property doesn't exist, this method
returns the specified default value.
@see System#getProperty(String, String)