javac: debug vs. optimized classes?

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Markus Dehmann - 04 Oct 2005 03:03 GMT

The external library I am using is compiled with debug info, and it's
pretty slow.

Could I expect it to be much faster if it were compiled with
-debug:none? What about javac -O? Does that still exist?

Are there speed comparisons between debug and optimized classes?

Thanks!
Markus

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Thomas Fritsch - 04 Oct 2005 03:25 GMT

"Markus Dehmann" <markus.dehmann@gmail.com> schrieb:

> The external library I am using is compiled with debug info, and it's
> pretty slow.
>
> Could I expect it to be much faster if it were compiled with -debug:none?

No, it will have exactly the same execution speed. The only things you can
expect are
(1) a smaller file size (by a few percent), and hence slightly shorter
download times
(2) less error information (due to missing line numbers in exception stack
traces)

> What about javac -O? Does that still exist?
>
> Are there speed comparisons between debug and optimized classes?

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Roedy Green - 04 Oct 2005 07:48 GMT

>No, it will have exactly the same execution speed.

Actually it would be slightly slower since some of your ram is chewed
up with line number offset tables and the like.

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Roedy Green - 04 Oct 2005 07:47 GMT

>Are there speed comparisons between debug and optimized classes?

There is an fairly way to find out and on your particular program
where it matters most:

use the -g:none option on Javac and execute with the public JRE
java.exe to try without debug.

use the -g option on javac and execute with the private JRE java.exe
in the JDK to try with debug.

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http://mindprod.com Again taking new Java programming contracts.

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javac: debug vs. optimized classes?

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