FileSystemResource can locate given spring bean configuration file from the specified path of the file system. Here we can pass either absolute path or relative path.
FileSystemResourceres = new FileSystemResource("src/com/example/cfgs/applicationContext.xml");
ClassPathResource can locate given spring bean configuration file from directories or jar files that are added to classpath/Build path.
ClassPathResource res = new ClassPathResource("applicationContext.xml");
Reference is here.