Way to make Java parent class method return object of child class

If you’re just looking for method chaining against a defined subclass, then the following should work:

public class Parent<T> {

  public T example() {
    System.out.println(this.getClass().getCanonicalName());
    return (T)this;
  }
}

which could be abstract if you like, then some child objects that specify the generic return type (this means that you can’t access childBMethod from ChildA):

public class ChildA extends Parent<ChildA> {

  public ChildA childAMethod() {
    System.out.println(this.getClass().getCanonicalName());
    return this;
  }
}

public class ChildB extends Parent<ChildB> {

  public ChildB childBMethod() {
    return this;
  }
}

and then you use it like this

public class Main {

  public static void main(String[] args) {
    ChildA childA = new ChildA();
    ChildB childB = new ChildB();

    childA.example().childAMethod().example();
    childB.example().childBMethod().example();
  }
}

the output will be

org.example.inheritance.ChildA 
org.example.inheritance.ChildA 
org.example.inheritance.ChildA 
org.example.inheritance.ChildB 
org.example.inheritance.ChildB