Class<? extends Foo> dynamicType = new ByteBuddy() .subclass(Foo.class) .method(ElementMatchers.named("bar")) .intercept(FixedValue.value("Hello World!")) .make() .load(getClass().getClassLoader()) .getLoaded(); Class<? extends Foo> dynamicType = new ByteBuddy() .subclass(Foo.class, ConstructorStrategy.Default.NO_CONSTRUCTORS) .modifiers(Modifier.PUBLIC) .defineField("name", String.class, Visibility.PRIVATE) .defineMethod("getName", String.class, Modifier.PUBLIC) .intercept(FieldAccessor.ofBeanProperty()) .make() .load(getClass().getClassLoader()) .getLoaded();