Load properties from files from classpath or file into Java system properties.
java -DpropertyLocations=file:config.properties
java -DpropertyLocations=file:config1.properties,anotherfolder/file:anotherconfig.properties
java -DpropertyLocations=classpath:/config.properties
firstname=John
lastname=Smith
fullname=${firstname} ${lastname}
// do once in code, e.g. static
PropertiesLoader.loadPropertiesLocationsIntoSystemProperties();
// get a property
String firstname = System.getProperty("firstname");