Is it worth to make a constant for an empty array in Java? -

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sometimes need return empty arrays fulfill classes contracts.

instead of creating empty array:

@override public string[] getdescriptiontexts() {     return new string[0]; // no texts }

i think may better re-use empty array constant:

public class strings {     public static final string[] empty_array = new string[0]; }  @override public string[] getdescriptiontexts() {     return strings.empty_array; // no texts }

is kind of optimization worth it?

they semantically equivalent, readable, using constant array (very slightly) more efficient performance , memory wise.

so go constant.

a quick micro benchmark shows difference 1 cpu cycle in terms of performance (0.3 nanoseconds, i.e. nothing really) , gc activity higher empty array creation (~10ms per 1000ms test or 1% of time spend in gc).

benchmark                                       mode  samples    score   error   units  c.a.p.so27167199.constant                       avgt       10    3.165 ± 0.026   ns/op c.a.p.so27167199.constant:@gc.count.profiled    avgt       10    0.000 ±   nan  counts c.a.p.so27167199.constant:@gc.count.total       avgt       10    0.000 ±   nan  counts c.a.p.so27167199.constant:@gc.time.profiled     avgt       10    0.000 ±   nan      ms c.a.p.so27167199.constant:@gc.time.total        avgt       10    0.000 ±   nan      ms  c.a.p.so27167199.newarray                       avgt       10    3.405 ± 0.051   ns/op c.a.p.so27167199.newarray:@gc.count.profiled    avgt       10  250.000 ±   nan  counts c.a.p.so27167199.newarray:@gc.count.total       avgt       10  268.000 ±   nan  counts c.a.p.so27167199.newarray:@gc.time.profiled     avgt       10   95.000 ±   nan      ms c.a.p.so27167199.newarray:@gc.time.total        avgt       10  108.000 ±   nan      ms

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