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Programmer Certification (OCPJP)

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sgopalan

Greenhorn

Posts: 1

posted 23 years ago

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Why can't a abstract method also be declared as
static?
Why is
static abstract void k12();
incorrect ?

Thomas Paul

mister krabs

Posts: 13974

posted 23 years ago

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Because static methods can't be overriden and abstract methods must be overridden.

Associate Instructor - Hofstra University
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Barkat Mardhani

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Posts: 787

posted 23 years ago

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Hi Paul:
I always wanted to find out if there is anything construct in Java that will allow polymorhism for static method methods?
Thanks
Barkat

Thomas Paul

mister krabs

Posts: 13974

posted 23 years ago

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Static methods do not participate in polymorphism. They can't because they are inlined at compile time.

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Shishio San

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Posts: 223

posted 23 years ago

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You can't use the static modifier with a method's prototype. When declaring an abstract method it's not implemented yet.

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Valentin Crettaz

Author & Gold Digger

Posts: 7617

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posted 23 years ago

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sgopalan,
Welcome to Javaranch

We'd like you to read the Javaranch Naming Policy and change your publicly displayed name (change it here) to comply with our unique rule. Thank you.
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Bishal P

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Posts: 43

posted 23 years ago

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Static methods do not participate in polymorphism. They can't because they are inlined at compile time.

Hey this is new to me. I only thought final methods were inlined at compile time. What other kinds of method can be inlined?

_ _____ _ <br />Used to be a Java Programmer but now I work on Microsoft Technologies - Word, Excel and Outlook!

Thomas Paul

mister krabs

Posts: 13974

posted 23 years ago

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private methods are also inlined. Making a private method final is redundant.

Associate Instructor - Hofstra University
Amazon Top 750 reviewer - Blog - Unresolved References - Book Review Blog

Bishal P

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Posts: 43

posted 23 years ago

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so bottomline is that any method that cannot be overridden can be inlined. Cool, thats easy to remember.

_ _____ _ <br />Used to be a Java Programmer but now I work on Microsoft Technologies - Word, Excel and Outlook!

Thomas Paul

mister krabs

Posts: 13974

posted 23 years ago

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What's even more interesting is that some methods are inlined at run time. See this thread:
https://coderanch.com/t/201812/Performance/java/Making-everything-compiler-allows-final
The bottom line is that any method that can possibly be inlined will end up being inlined as soon as possible, either at compile time or runtime.

Associate Instructor - Hofstra University
Amazon Top 750 reviewer - Blog - Unresolved References - Book Review Blog

Vin Kris

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Posts: 154

posted 23 years ago

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Paul, will the methods be inlined regardless of the size of the method? wouldn't that be an overhead? If a method that is eligible for inlining has a huge size, and also invoked a lot of times from a single method, wouldn't inlining be a dis-advantage? (because i read somewhere that the maximum size of a single method is ~64k bytes)
I think the C/C++ compilers take these details into consideration before inlining. Any links on this topic?

Thomas Paul

mister krabs

Posts: 13974

posted 23 years ago

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Originally posted by Vin Kris:
(because i read somewhere that the maximum size of a single method is ~64k bytes)

I am sure Java takes this into account but... a method in Java > 64k bytes!!! Was it written by a COBOL programmer?
(This is not meant as a swipe at COBOL programmers. It is simply the case that COBOL programmers generally write large scale procedural top down programs.)

Associate Instructor - Hofstra University
Amazon Top 750 reviewer - Blog - Unresolved References - Book Review Blog

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