Question

I'm wondering if there are any known performance differences in terms of the Java 7 diamond operator versus the language construct for previous versions of Java.

Basically, is it faster to use this:

List<String> myList = new ArrayList<>()
Map<String, Integer> myMap = new HashMap<>()

or to use this:

List<String> myList = new ArrayList<String>() 
Map<String, Integer> myMap = new HashMap<String, Integer>()

Are they the same speed?

Était-ce utile?

La solution

The generated bytecode is the same. The new diamond operator is purely implemented to save programmers from having to redundantly specify the type twice.

Autres conseils

Negative. Due to type erasure, the diamond operator (and generics in general) have the same run-time performance as they always have (e.g. at run-time Collections just hold Object(s)).

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