Singleton Pattern

Scenario: You need to ensure that a class only has one instance throughout the application lifecycle, such as a configuration manager.

  • Question: How would you implement a Singleton pattern in Java to manage a global configuration setting?

Scenario: You have a class that represents a logging service, and you want to ensure there is only one instance managing all log outputs.

  • Question: What is a thread-safe approach to implement the Singleton pattern for a logging service in Java?
Scenario: Your application requires a single instance of a database connection pool.
  • Question: How would you use the Singleton pattern to manage a database connection pool efficiently?
Scenario: A caching system in your application needs to be a single instance to ensure consistency across all operations.
  • Question: Describe how you would apply the Singleton pattern to design a caching system.
Scenario: You need to control access to a shared resource across multiple threads.
  • Question: What techniques can be used to implement a thread-safe Singleton pattern in Java?

Scenario: You need a single instance of a network connection manager that handles multiple connections.

  • Question: How would you implement the Singleton pattern to ensure only one network connection manager instance is created?

Scenario: A settings manager in your application needs to be accessed globally to provide consistent configurations.

  • Question: Describe how you would use the Singleton pattern to implement a settings manager that can be accessed globally.

Scenario: You need to ensure that a class used for resource pooling (e.g., thread pool) only has a single instance.

  • Question: What is a common approach to implementing the Singleton pattern for a resource pool?

Scenario: You want to control access to a shared cache that should be initialized only once.

  • Question: How can you use the Singleton pattern to implement a cache that is initialized only once?

Scenario: Your application has a global logging service that must be used throughout the application.

  • Question: How would you ensure that there is only one instance of the logging service using the Singleton pattern?

Scenario: Your application has a single point of access for managing API keys.

  • Question: How would you use the Singleton pattern to manage API keys across your application?

Scenario: You need a single instance of a system configuration manager that ensures consistent application settings.

  • Question: How can you implement a thread-safe Singleton pattern to manage system configurations?

Scenario: Your logging framework requires a single instance to handle log file writing across multiple threads.

  • Question: How would you use the Singleton pattern to ensure only one instance of the logging framework is used?

Scenario: You need a Singleton instance for managing user sessions in a web application.

  • Question: How would you implement the Singleton pattern to manage user sessions effectively?

Scenario: Your application requires a Singleton instance to coordinate access to a shared resource, such as a printer.

  • Question: Describe how you would use the Singleton pattern to control access to a shared printer resource.