Spring: Autowired or "Plain" Call by using the #Configuration annotations? - spring

Question

i have the following JAVA supported in Spring 4.0.3 configuration, that have two DataSource und JdbcTemplate beans:
#PropertySource("classpath:db.properties")
#Configuration
public class DBConfiguration {
.....
#Autowired
Environment env;
#Bean
public DataSource internalDataSource() {
DriverManagerDataSource dataSource = new DriverManagerDataSource();
// init dataSource setters for DATABASE_1
return dataSource;
}
#Bean
public DataSource publicDataSource() {
DriverManagerDataSource dataSource = new DriverManagerDataSource();
// init dataSource setters for DATABASE_2
return dataSource;
}
}
...
#Bean
public JdbcTemplate internalJDBCTemplate() {
return new JdbcTemplate(internalDataSource());
}
#Bean
public JdbcTemplate publicJDBCTemplate() {
return new JdbcTemplate(publicDataSource());
}
___
I have other configuration bean class, that autowires the first configuration and calls internalDataSource() method:
#Import(DBConfiguration.class)
#Configuration
public class AuthConfiguration {
#Autowired
private DBConfiguration dbConfiguration;
#Autowired
private TokenStore tokenStore;
#Bean
public TokenStore tokenStore() {
return new JdbcTokenStore(dbConfiguration.securityDataSource());
}
...}
I suppose, that even DBConfiguration was imported and autowired into AuthConfiguration class, the each call of dbConfiguration.securityDataSource() will be cause the new DriverManagerDataSource() with each time intializing of data source.
Is it correkt or not?

Answer 1

The default bean scope in Spring is singleton so the data source will be initialized only once.
When a DI container creates bean TokenStore it gets a bean defined in DBConfiguration by the securityDataSource method. But it doesn't call the method directly, it takes a bean instance from the DI container. An initialization of all beans is done by Spring transparently to a developer.
Note that classes annotated with #Configuration are just a definition for the framework and they aren't executed directly.