What is the different between:

Question

1.24/5 (3 votes)

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ArrayList<class> Foo = new ArrayList<class>();
AND
ArrayList<class> Foo = new ArrayList<>();

What I have tried:

this form is not necessary!!!!!!!!!!!!!!!!!!!!!!!

Posted 2-Jan-18 4:16am

Hellen Micheal

Updated 2-Jan-18 4:20am

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Richard MacCutchan 2-Jan-18 10:30am

Both appear to be the same in my sample test. What results did you get?

Hellen Micheal 3-Jan-18 7:26am

same

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Thomas Daniels · Accepted Answer · 2018-01-02T04:20:00

Because you already specified the type once, you don't need to do it twice. The compiler knows the type. This is called "type inference": Type Inference for Generic Instance Creation[^]

Quote:
You can replace the type arguments required to invoke the constructor of a generic class with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context. This pair of angle brackets is informally called the diamond.