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A comment on _Application.Run(Object, Object, Object, Object, Object, Object, Object, Object.

Re:_Application.Run(Object, Object, Object, Object, Object, ... by wiradikusuma on Monday January 10, 2022 @05:12AM (#29872645)
I first saw this "hardcoded" varargs in Scala e.g. https://www.scala-lang.org/api/2.12.2/scala/Tuple22.html (replace 22 to 1-21). I guess it's platform (JVM) limitation? Newer Java also has something like this, but I can't remember which class.
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Re:_Application.Run(Object, Object, Object, Object, Object, ... by sevenproxies on Monday January 10, 2022 @05:37AM (#29872811)
Another example is Java's java.util.Map.of. It's a convenient method to construct a map in a single statement.

https://docs.oracle.com/en/java/javase/11/docs/api/java.base...

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Re:_Application.Run(Object, Object, Object, Object, Object, ... by mileza on Monday January 10, 2022 @09:54AM (#29875693)
This kind of function overload is present everywhere in the Java collection framework (and probably other libraries). It is a performance optimization (variadic arguments in Java require creating an array), and variadiac overloads also exist (Map.of needs a list of Map.Entry for type safety) for creating collections of any size.

https://docs.oracle.com/en/java/javase/11/docs/api/java.base...

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Re:_Application.Run(Object, Object, Object, Object, Object, ... by laurensr on Monday January 10, 2022 @06:28AM (#29873192)
Do note that the created map is immutable. However, you could pass the created map to the constructor HashMap (or another type) to obtain a mutable copy of the Map created using Map.of
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Re:_Application.Run(Object, Object, Object, Object, Object, ... by qsort on Monday January 10, 2022 @06:11AM (#29873080)
It doesn't have the equivalent of variadic templates, which means you can't have something like std::tuple unless you either codegen it or make it not type-safe.

I did the exact same thing in Java for an internal library in order to provide type-safe Unit, Singleton<T1>, Pair<T1, T2>, etc.

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Re:_Application.Run(Object, Object, Object, Object, Object, ... by paradaux on Monday January 10, 2022 @05:26AM (#29872746)
I don't think I have seen classes with many parameters to avoid varargs in Java, however I have certainly seen classes with dozens of Type Parameters, I believe some form of code generation was responsible.

Can't for the life of me find that class again.

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Re:_Application.Run(Object, Object, Object, Object, Object, ... by jdmichal on Monday January 10, 2022 @10:55AM (#29876718)
SLF4J Loggers define up to two arguments for precisely this purpose:

https://www.slf4j.org/apidocs/org/slf4j/Logger.html#error(ja......)

> This form avoids superfluous string concatenation when the logger is disabled for the ERROR level. However, this variant incurs the hidden (and relatively small) cost of creating an Object[] before invoking the method, even if this logger is disabled for ERROR. The variants taking one and two arguments exist solely in order to avoid this hidden cost.

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Re:_Application.Run(Object, Object, Object, Object, Object, ... by vips7L on Monday January 10, 2022 @11:05AM (#29876871)
Look at Set.of and Map.of. Lots of overloads to avoid allocating the vararg array.
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Re:_Application.Run(Object, Object, Object, Object, Object, ... by vips7L on Monday January 10, 2022 @10:00AM (#29875810)
It’s to prevent allocating the array for varargs.
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Re:_Application.Run(Object, Object, Object, Object, Object, ... by revel on Monday January 10, 2022 @04:25PM (#29882807)
Yes. This used to be one of those things that made a significant difference but probably doesn't matter any more. I say "probably" because I haven't seen any code like this that wasn't spat out from a generator in a long time
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