We have the following example:

@SpringBootApplicationpublic class In28minutesScopeApplication {    private static Logger LOGGER = LoggerFactory.getLogger(In28minutesScopeApplication.class);    public static void main(String[] args) {        // Application Context        ApplicationContext applicationContext =                SpringApplication.run(In28minutesScopeApplication.class, args);        PersonDAO personDAO = applicationContext.getBean(PersonDAO.class);        PersonDAO personDAO1 = applicationContext.getBean(PersonDAO.class);        LOGGER.info("{}", personDAO);        LOGGER.info("{}", personDAO.getJdbcConnection());        LOGGER.info("{}", personDAO1);        LOGGER.info("{}", personDAO1.getJdbcConnection());    }}

@Componentpublic class PersonDAO {    @Autowired    JDBCConnection jdbcConnection;    public JDBCConnection getJdbcConnection() {        return jdbcConnection;    }    public void setJdbcConnection(JDBCConnection jdbcConnection) {        this.jdbcConnection = jdbcConnection;    }}@Componentpublic class JDBCConnection {    public JDBCConnection () {        System.out.println("JDBC Connection");    }}

 

The idea is to understand in different cases, how those instanse are created.

Currently when running the application, we got:

com.example.in28minutes.scope.PersonDAO@6c61a903com.example.in28minutes.scope.JDBCConnection@59d4cd39 com.example.in28minutes.scope.PersonDAO@6c61a903com.example.in28minutes.scope.JDBCConnection@59d4cd39

Each class share the same instanse.

 

What if we want that 'PersonDAO' using Singleton but JDBCConnection use 'Prototype'?

@Component@Scope(ConfigurableBeanFactory.SCOPE_SINGLETON)public class PersonDAO {    @Autowired    JDBCConnection jdbcConnection;    public JDBCConnection getJdbcConnection() {        return jdbcConnection;    }    public void setJdbcConnection(JDBCConnection jdbcConnection) {        this.jdbcConnection = jdbcConnection;    }}@Component@Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)public class JDBCConnection {    public JDBCConnection () {        System.out.println("JDBC Connection");    }}

 

In the end, we got the same result:

com.example.in28minutes.scope.PersonDAO@14008db3com.example.in28minutes.scope.JDBCConnection@16aa8654com.example.in28minutes.scope.PersonDAO@14008db3com.example.in28minutes.scope.JDBCConnection@16aa8654

 

If we really want JDBCConnection use a different instance, we can add Proxy to it:

@Component@Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE, proxyMode = ScopedProxyMode.TARGET_CLASS)public class JDBCConnection {    public JDBCConnection () {        System.out.println("JDBC Connection");    }}