code: public static String getProperty(String key, String def) {
  		return System.getProperty(key, def);
  	}
docs: 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)