You may desire or be required to use XML as the primary mechanism for configuring the container, but wish to selectively use @Configuration classes to define certain beans. For such cases, JavaConfig provides ConfigurationPostProcessor, a Spring BeanPostProcessor capable of processing @Configuration classes.

<beans>
    <!-- first, define your individual @Configuration classes as beans -->
    <bean class="com.myapp.config.AppConfig"/>
    <bean class="com.myapp.config.DataConfig"/>

    <!-- be sure to include the JavaConfig bean post-processor -->
    <bean class="org.springframework.config.java.process.ConfigurationPostProcessor"/>
</beans>
                

Then, bootstrap an XML ApplicationContext:

ApplicationContext context = new ClassPathXmlApplicationContext("application-config.xml");
                

The beans defined in AppConfig and DataConfig will be available via context.

<beans>
    <!-- a possible "configurable configuration" -->
    <bean class="org.my.company.config.AppConfiguration">
        <property name="env" value="TESTING"/>
        <property name="monitoring" value="true"/>
        <property name="certificates" value="classpath:/META-INF/config/MyCompany.certs"/>
    </bean>
    <!-- JavaConfig post-processor -->
    <bean class="org.springframework.config.java.process.ConfigurationPostProcessor"/>
</beans>
                    

The @ImportXml annotation is provided to support importing beans defined in XML into @Configuration classes.

<beans>
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="url" value="jdbc:hsqldb:hsql://localhost:9001"/>
        <property name="driverClassName" value="org.hsqldb.jdbcDriver"/>
        <property name="username" value="sa"/>
        <property name="password" value=""/>
    </bean>
</beans>

            

@Configuration
@AnnotationDrivenConfig // enable the @Autowired annotation
@ImportXml("classpath:com/company/app/datasource-config.xml")
public class Config {
    // autowire the DataSource bean declared in datasource-config.xml
    @Autowired DataSource dataSource;

    @Bean
    public FooRepository fooRepository() {
        // inject the autowired-from-XML dataSource
        return new JdbcFooRepository(dataSource);
    }

    @Bean
    public FooService fooService() {
        return new FooServiceImpl(fooRepository());
    }
}