java中的类，BasicDataSource,DataSource,ComboPooledDataSource这三个类有啥关系

Question

类:
BasicDataSource dataSource = new BasicDataSource();
类:
pro.load(DbcpTest.class.getClassLoader().getResourceAsStream("dbcpConfig.properties"));
DataSource dataSource = BasicDataSourceFactory.createDataSource(pro);
类:
ComboPooledDataSource dataSource = new ComboPooledDataSource();

这三个类之间有啥关系，很疑惑，求指导呀。