Learn Singleton Pattern — a key concept for LLD interviews.
Interactive — Try it yourself!
How to use
1Select "Singleton" tab in the Pattern Playground
2Click "Get Instance" multiple times — notice the ID stays the same!
3Click "Try new()" — blocked! Only one instance allowed
4See the connection count: all code shares one pool
In a nutshell
Singleton ensures a class has only ONE instance globally. Like a database connection pool — you want one shared pool, not 100 separate ones. Use when: shared resource, global config, connection pool.