How does classes impact performance or memory usage?

In Java, classes significantly impact performance and memory usage. When you create a class, you are defining a blueprint for objects that include data members (attributes) and methods (functions) that operate on the data. The way you structure your classes can lead to different performance implications, especially with memory allocation and garbage collection.

Creating a class with numerous attributes can increase memory usage, as each instance of the class will consume memory for those attributes. Moreover, if a class is designed with a deep inheritance hierarchy, it can lead to increased method lookup time, thus impacting performance.

Additionally, if your class design involves creating many small objects, it may lead to higher overhead due to frequent garbage collections. It’s essential to balance the number of objects you create and their lifetime to optimize both performance and memory usage.