How to conditionally declare Bean when multiple profiles are not active?

Since Spring 5.1.4 (incorporated in Spring Boot 2.1.2) it is possible to use a profile expression inside profile string annotation. So:

In Spring 5.1.4 (Spring Boot 2.1.2) and above it is as easy as:

@Component
@Profile("!a & !b")
public class MyComponent {}

In Spring 4.x and 5.0.x:

There are many approaches for this Spring versions, each one of them has its pro's and con's. When there aren't many combinations to cover I personally like @Stanislav answer with the @Conditional annotation.

Other approaches can be found in this similar questions:

Spring Profile - How to include AND condition for adding 2 profiles?

Spring: How to do AND in Profiles?

If you have a single profile you could simply use a @Profile annotation with the not operator. It also accepts multiple profiles, but with the OR condition.

So, the alternative solution is to use a custom Condition with the @Conditional annotation. Like so:

public class SomeCustomCondition implements Condition {
  @Override
  public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {

    // Return true if NOT "a" AND NOT "b"
    return !context.getEnvironment().acceptsProfiles("a") 
                  && !context.getEnvironment().acceptsProfiles("b");
  }
}

And then annotate your method with it, like:

@Bean
@Conditional(SomeCustomCondition.class)
public MyBean myBean(){/*...*/}