Feature flags concept in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a feature flag in software development?

A feature flag is a switch in the code that lets developers turn features on or off without changing the code or redeploying the app. It helps control which features users see.

intermediate

How do feature flags help in continuous delivery?

Feature flags allow teams to release new features safely by enabling them only for some users or in testing environments, reducing risk and making deployment faster.

intermediate

In Spring Boot, where can feature flags be typically stored?

Feature flags in Spring Boot can be stored in configuration files (like application.properties), databases, or external services, allowing dynamic control without code changes.

advanced

What is a common risk of using feature flags if not managed properly?

If feature flags are not cleaned up after use, they can clutter the code and cause confusion, making maintenance harder and increasing the chance of bugs.

intermediate

Explain the difference between a permanent and a temporary feature flag.

Temporary feature flags are used for short-term testing or rollout and removed after. Permanent flags control features that may always be optional or configurable.

What is the main purpose of a feature flag?

A To improve database performance

B To store user passwords securely

C To turn features on or off without redeploying

D To manage user sessions

Feature flags let developers enable or disable features dynamically without changing the code or redeploying.

Where can feature flags be stored in a Spring Boot application?

A In configuration files, databases, or external services

B Only in Java code

C Only in environment variables

D Only in the user interface

Spring Boot supports storing feature flags in config files, databases, or external services for flexibility.

What is a risk of leaving old feature flags in the code?

A They automatically delete themselves

B They make the code easier to read

C They improve app speed

D They clutter the code and cause confusion

Old feature flags can clutter code and make maintenance harder if not removed.

Which of these is NOT a benefit of using feature flags?

A Instant bug fixes without code changes

B Controlling feature visibility

C Testing features in production

D Safe feature rollout

Feature flags control feature visibility but do not fix bugs instantly without code changes.

What type of feature flag is used for long-term optional features?

A Temporary feature flag

B Permanent feature flag

C Debug flag

D Security flag

Permanent feature flags control features that remain optional or configurable long-term.

Describe how feature flags improve the deployment process in Spring Boot applications.

Think about how you can control features without changing the app code.

Explain the best practices for managing feature flags to avoid technical debt.

Consider how to keep code clean and understandable.