What is the difference between empty generics<> and , notation in java?

Asked Aug 23 '16 at 08:19

Active Aug 23 '16 at 08:35

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I know E and T can be used interchangeably in Java generics. I also looked up this Java Generics ? , E and T what is the difference? answer , but couldn't find much information on empty generics and how is it different ? Thanks

EDIT: I don't agree with the duplicate. The question link provided doesn't answer my question i.e the difference between <> and < E > or < T >

edited May 23 '17 at 12:01

Community

asked Aug 23 '16 at 08:19

Always_Beginner

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You mean [diamond operator](https://docs.oracle.com/javase/tutorial/java/generics/types.html)? – Maroun Aug 23 '16 at 08:22
What do you mean by "empty"? Like "<>" ? Or the wildcards? – Fildor Aug 23 '16 at 08:22
Yes , sorry for not mentioning it – Always_Beginner Aug 23 '16 at 08:22
Aren't `E` and `T` just names? – byxor Aug 23 '16 at 08:22
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Actually, T and E are the most used letters but you can use what you want, even complete words, in order to enhance readability. – Héctor Aug 23 '16 at 08:22
`T`, `E` (or any other word you wish to put) can be referenced later on on your code, `?` cannot. – Ray O'Kalahjan Aug 23 '16 at 08:24
So , can we replace '<>' with ( or ) and vice versa ? – Always_Beginner Aug 23 '16 at 08:29
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@plutonium No, they are different things. ( or ) is a generic type. <> is only used when instantiating a class and only when Java can infer the type it should go there. So, it's not really a type, it's just a tool so you don't have to write the type if it's obvious. is like ( or ) except that every time you write > in your code, it will be a different type. Hope this helps. – Ray O'Kalahjan Aug 23 '16 at 09:19
@RayO'Kalahjan Thanks for the answer , BTW can we use or when instantiating a class instead of <> ? – Always_Beginner Aug 23 '16 at 09:34
@plutonium Yes, you can. In fact, there was no <> until Java 7. – Ray O'Kalahjan Aug 23 '16 at 09:38

What is the difference between empty generics<> and , notation in java?

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