This version is still in development and is not considered stable yet. For the latest stable version, please use Spring Framework 6.2.5!

Programmatic Bean Registration

As of Spring Framework 7, a first-class support for programmatic bean registration is provided via the BeanRegistrar interface that can be implemented to register beans programmatically in a flexible and efficient way.

Those bean registrar implementations are typically imported with an @Import annotation on @Configuration classes.

Java
Kotlin

@Configuration
@Import(MyBeanRegistrar.class)
class MyConfiguration {
}

@Configuration
@Import(MyBeanRegistrar::class)
class MyConfiguration {
}

You can leverage type-level conditional annotations (@Conditional, but also other variants) to conditionally import the related bean registrars.

The bean registrar implementation uses BeanRegistry and Environment APIs to register beans programmatically in a concise and flexible way. For example, it allows custom registration through an if expression, a for loop, etc.

Java
Kotlin

class MyBeanRegistrar implements BeanRegistrar {

    @Override
    public void register(BeanRegistry registry, Environment env) {
        registry.registerBean("foo", Foo.class);
        registry.registerBean("bar", Bar.class, spec -> spec
                .prototype()
                .lazyInit()
                .description("Custom description")
                .supplier(context -> new Bar(context.bean(Foo.class))));
        if (env.matchesProfiles("baz")) {
            registry.registerBean(Baz.class, spec -> spec
                    .supplier(context -> new Baz("Hello World!")));
        }
    }
}

class MyBeanRegistrar : BeanRegistrarDsl({
    registerBean<Foo>()
    registerBean(
        name = "bar",
        prototype = true,
        lazyInit = true,
        description = "Custom description") {
            Bar(bean<Foo>())
    }
    profile("baz") {
        registerBean { Baz("Hello World!") }
    }
})

Bean registrars are supported with Ahead of Time Optimizations, either on the JVM or with GraalVM native images, including when instance suppliers are used.