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공부

[Java] Generic method

seunggabi 승가비 2020. 6. 7. 15:45
private Object o;

public <T> List<T> magicalListGetter(Class<T> klazz) {
    List<T> list = new ArrayList<>();
    list.add(klazz.cast(o));
    
    try {
        list.add(klazz.getConstructor().newInstance());
    }
    return list;
}

https://stackoverflow.com/questions/17840483/how-to-have-java-method-return-generic-list-of-any-type

 

How to have Java method return generic list of any type?

I would like to write a method that would return a java.util.List of any type without the need to typecast anything: List users = magicalListGetter(User.class); List ve...

stackoverflow.com

 

public <T extends Animal> T callFriend(String name, Class<T> type) {
    return type.cast(friends.get(name));
}

jerry.callFriend("spike", Dog.class).bark();
jerry.callFriend("quacker", Duck.class).quack();

https://stackoverflow.com/questions/450807/how-do-i-make-the-method-return-type-generic

 

How do I make the method return type generic?

Consider this example (typical in OOP books): I have an Animal class, where each Animal can have many friends. And subclasses like Dog, Duck, Mouse etc which add specific behavior like bark(), q...

stackoverflow.com

 

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