Autoloading is not thread-safe and hence we need to make sure that all constants are loaded when application boots. The concept of loading all the constants even before they are actually needed is called “Eager loading”. In a way it is opposite of “Autoloading”. In the case of “Autoloading” the application does not load the constant until it is needed. Once a class is needed and it is missing then the application starts looking in “autoloading paths” to load the missing class.
