Support the concept of "traits"

Traits...

• are stateful components that can be mixed in classes
• support composition and inheritance
• are compatible with static type checking and static compilation
• support dynamic approaches as well
• can be mixed in at runtime
• solve the usual diamond problem of inheritance
• support specific overriding rules in case of method conflicts

See here for detailed documentation for more information:
http://beta.groovy-lang.org/docs/groovy-2.3.0-SNAPSHOT/html/documentation/core-traits.html