How can I make the return type of a method generic

0 votes

Is there a way to figure out the return type at runtime without the extra parameter using instanceof? Or at least by passing a class of the type instead of a dummy instance.
I understand generics are for compile time type-checking, but is there a workaround for this?

May 19, 2018 in Java by Parth
• 4,640 points
758 views

1 answer to this question.

0 votes

First of all, define callFriend:

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

Then call it as such:

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

This code has the benefit of not generating any compiler warnings. This is really just an updated version of casting from the pre-generic days and doesn't add any additional safety.

answered May 19, 2018 by sharth
• 3,370 points

Related Questions In Java

0 votes
2 answers

What is the use of toString method in Java and how can I use it ?

Whenever you require to explore the constructor ...READ MORE

answered Aug 23, 2018 in Java by Daisy
• 8,140 points
4,053 views
0 votes
1 answer

How do I create a Java string from the contents of a file?

If you're looking for an alternative that ...READ MORE

answered Apr 19, 2018 in Java by Rishabh
• 3,620 points
1,122 views
+1 vote
6 answers

How can I separate the digits of an int number in Java?

You can also have a look here: To ...READ MORE

answered Dec 9, 2020 in Java by Roshni
• 10,520 points
208,919 views
0 votes
2 answers

How can I sort values of a Map in Java using its key

Assuming TreeMap is not good for you ...READ MORE

answered Oct 10, 2018 in Java by Sushmita
• 6,920 points
1,154 views
0 votes
2 answers

how can we Create instance for generic type in java

private static class SomeContainer<E> { ...READ MORE

answered Aug 27, 2018 in Java by Sushmita
• 6,920 points
26,713 views
0 votes
2 answers

How can I invoke a method when the method name is in the form of a given string?

You could probably use method invocation from reflection: Class<?> ...READ MORE

answered Aug 19, 2019 in Java by Sirajul
• 59,230 points
3,015 views
0 votes
2 answers

How do i create generic array in Java

as first tip you cannot assign value ...READ MORE

answered Feb 13, 2020 in Java by sama
17,178 views
0 votes
1 answer

How to calculate method execution time in Java ?

Use the following code : new Timer(""){{ ...READ MORE

answered May 25, 2018 in Java by Rishabh
• 3,620 points
1,658 views
0 votes
2 answers

How can I get the filenames of all files in a folder which may or may not contain duplicates

List<String> results = new ArrayList<String>(); File[] files = ...READ MORE

answered Sep 12, 2018 in Java by Sushmita
• 6,920 points
1,863 views
0 votes
2 answers

How can I convert a String variable to a primitive int in Java

 Here are two ways illustrating this: Integer x ...READ MORE

answered Aug 20, 2019 in Java by Sirajul
• 59,230 points
2,232 views
webinar REGISTER FOR FREE WEBINAR X
REGISTER NOW
webinar_success Thank you for registering Join Edureka Meetup community for 100+ Free Webinars each month JOIN MEETUP GROUP