@Conditional and @ConditionalOnProperty

@Conditional and @ConditionalOnProperty annotation allow us to create beans conditionally.

There are multiple ways to create/instantiate bean conditionally. Below are the common two ways:

Based Condition class implementation and @Conditional annotation:

Create EnableStudentService class implementing Condition interface and override the matches() method for writing custom condition logic which will be returning true or false.

Declare @Conditional annotation just below to @Bean annotation to create bean instance conditionally at runtime.

Based on property using @ConditionalOnProperty annotation:

@ConditionalOnProperty allow us to create bean based on property conditions:

Here, the studentService() bean class will only be created if practice.feature.enabled=true in application.properties file.

matchIfMissing = false ensures that if the property is missing, the bean won’t be created.

Note: The @Autowired(required = false) annotation prevents errors by allowing the application to proceed even if the bean is unavailable.

Important Note:

• @Conditional and @ConditionalOnProperty helps us to register bean dynamically based on conditions.
• It also provides us the flexibility to enable or disable bean instantiation without modifying the code.
• Minimizes the creation of unnecessary beans.