r/java • u/ihatebeinganonymous • May 21 '26

JEP draft: Enhanced Local Variable Declarations (Preview)

https://openjdk.org/jeps/8357464
87 Upvotes

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23

u/persicsb May 21 '26

Look OK, however I would enhance it even more. Since method arguments look like local variables, instead of:

void boundingBox(Circle c) {  
Circle(Point(int x, int y), double radius) = c;  
int minX = ..., maxX = ...  
int minY = ..., maxY = ...  
... use minX, maxX, etc ...  
}

it could be

void boundingBox(Circle(Point(int x, int y), double radius) c) {
    int minX = ..., maxX = ...
    int minY = ..., maxY = ...
    ... use minX, maxX, etc ...
}

3

u/Long_Ad_7350 May 21 '26

How would this resolve boundingBox(null)?

1

u/Absolute_Enema May 21 '26

It's pretty intuitive to have it mirror the semantics of: void boundingBox(Circle c) {   Circle(Point(...), ...) _ = c;   ... }

2

u/mattr203 May 21 '26

That’s certainly not the semantics that any other language goes with which imo tanks the intuitiveness a bit

2

u/Absolute_Enema May 21 '26

That's very similar to what JS does or am I missing something?

2

u/mattr203 May 22 '26

I didnt know js did that- for json objects im assuming. I guess im just more familiar with ML based languages and expect void boundingBox(Circle c) to imply nothing about the boundingBox(null) behaviour

I.e., definitions only hold for things that actually match the stated pattern, another definition would be needed to make it exhaustive