Application.properties basics in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the application.properties file in a Spring Boot project?

It is used to configure application settings like server port, database connection, and other properties in a simple key-value format.

beginner

How do you set the server port to 8081 in application.properties?

Add the line server.port=8081 to the application.properties file.

beginner

Can you use application.properties to configure database connection details? Give an example.

Yes. For example:<br>spring.datasource.url=jdbc:mysql://localhost:3306/mydb<br>spring.datasource.username=root<br>spring.datasource.password=secret

intermediate

What happens if you have conflicting properties in application.properties and application.yml?

Spring Boot uses a priority order. Usually, application.properties and application.yml are merged, but if the same property is defined in both, the last one loaded wins. It's best to avoid conflicts.

intermediate

How can you access a property defined in application.properties inside your Spring Boot Java code?

You can use the @Value annotation, for example:<br>@Value("${property.name}")<br>private String propertyName;

Which file format is used for application.properties?

A JSON format

B XML format

C Key-value pairs separated by '='

D YAML format

application.properties uses simple key-value pairs separated by '='.

How do you change the default server port in Spring Boot using application.properties?

A server.port=8081

B port=8080

C server.port=8080

D serverPort=8081

The correct property to change the port is server.port.

Which annotation allows you to inject a property value from application.properties into a Spring Boot component?

A @Autowired

B @PropertySource

C @Component

D @Value

@Value is used to inject property values.

If you want to set a database URL in application.properties, which prefix is commonly used?

A spring.datasource.

B database.url.

C db.connection.

D spring.db.url.

Spring Boot uses spring.datasource. prefix for database settings.

What is the file name for the default Spring Boot configuration file using properties format?

A application.yaml

B application.properties

C config.properties

D spring.properties

The default configuration file is application.properties.

Explain how to configure the server port and database connection in application.properties.

Think about key-value pairs for server and database settings.

Describe how to access a property from application.properties inside a Spring Boot Java class.

Consider how Spring Boot injects configuration values.