How to use multiple upper bounds in generics

问题

I have a Interface Foo which has a generic type -

 public interface Foo<T> {  
     boolean apply(T t);  
 }

Having another class Bar which implements this interface but what I want is the generic Type of Bar should be a Collection of type Interface A and B, With the below definition its giving compiler error -

public class Bar implements Foo<Collection<? extends A & B>>{
  @Override
  public boolean apply(Collection<? extends A & B> collect){
   ...
  }  
}

Can you suggest the correct way to achieve this?

I can use multiple bounds at method level only?

回答1:

Wouldn't this work?

public class Bar<T extends A & B> implements Foo<Collection<T>>{
  @Override
  public boolean apply(Collection<T> collect){
   ...
  }  
}

来源：https://stackoverflow.com/questions/5034231/how-to-use-multiple-upper-bounds-in-generics