1:
private List<String> blacklist = new ArrayList<String>();
2:
private List<String> blacklist = new ArrayList<>();
Are there any advantages using the first or the second one in compile time or performance in nanoseconds?
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Bob
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1The latter is exclusively Java 7+, the other one isn't. Performance in *nano*seconds? – Dave Newton Apr 02 '15 at 14:38
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So you want to gain 1 nanosecond? At compile time? Also, @DaveNewton, the first one is Java 7+ too! – Olivier Grégoire Apr 02 '15 at 14:38
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1@OlivierGrégoire Clarified for the pedantic. – Dave Newton Apr 02 '15 at 14:39
2 Answers
2
Both statements are semantically the same.
The 2nd example is using Diamond operator from Java 7 and so will be a little bit slower at compile time. At runtime they will have exactly the same performance as the generics information will be completely removed.
Crazyjavahacking
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1You probably won't notice the "little bit slower" compile time. The diamond operator is a simple type inference feature of the compiler. – Binkan Salaryman Apr 02 '15 at 14:43
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Not necessarily, it is a little bit more complicated as you can use the wildcards as well. – Crazyjavahacking Apr 02 '15 at 14:45
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There is no difference. In the second case, the compiler infers the generic type of the ArrayList.
Andy Turner
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