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Favour Direct Class References

Be aware of the drawbacks of using Class.getClass() to obtain a Class reference. Class.class can be used at compile time, whilst getClass() is only available at runtime.

Starting with the definitions of each:

  • .getClass() - returns "The Class object that represents the runtime class of this object."
  • .class - returns "The Class object that represents the entity (class, interface, array class, primitive type, or void) named by the binary name, as specified by the Java Language Specification."


class Building {
private int doors;

class House extends Building {}
House building1 = new Building();

Class runtimeType = building1.getClass();
Class staticType = Building.class;

assertSame(runtimeType, staticType); // false

Additionally getClass() requires a virtual function dispatch to be performed, which can be expensive. Take the example below to highlight a potential pitfall:


This can be a common (non-fatal) pitfall when logging, as the logger now has to be instantiated as a non-static variable. The following example shows a common scenario:

public class Building {
private static final Logger LOGGER = LoggerFactory.getLogger(getClass());


The issue here is that each time the Building class is instantiated, a new Logger instance is created, whereas if

private static final Logger LOGGER = LoggerFactory.getLogger(Building.class);

was used, only a single instance would be shared across all instantiations.

Primitive Types

The getClass() method is also unusable for any class that cannot be instantiated (e.g. primitive, interface , abstract, etc.) primitive types, whereas the .class method can still be used.

Class runtimeType = int.getClass();


Only use getClass() when you need to obtain a Class reference at runtime, and not at compile time.