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JDK's Bug?! java.util.Properties don't save comments!

Yashnoo lyo
Ranch Hand

Joined: Feb 17, 2003
Posts: 152
Hi friends:
I want to edit a file using class java.util.Properties. My file is:

After I run my application,all the comment is lost!
My code is:

After I run my code,the change to this:

Where is my comments!? They are deleted by java.util.Properties!
All my comments information lost! why Properties class don't save comment? ;-(

When I face C# and Java I choose Java.
Jesper de Jong
Java Cowboy
Saloon Keeper

Joined: Aug 16, 2005
Posts: 15100

The specifications of the Properties class and the load(...) and store(...) methods do not say anything about preserving your comments in the file.

This is not a JDK bug - the Properties class was just not designed to save files with comments etc. in exactly the same format as what you typed in by hand.

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Christophe Verré

Joined: Nov 24, 2005
Posts: 14688

I agree with Jesper.

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Ulf Dittmer

Joined: Mar 22, 2005
Posts: 42965
If you absolutely need to preserve comments when programmatically modifying properties files, have a look at the UberProperties class.
I agree. Here's the link:
subject: JDK's Bug?! java.util.Properties don't save comments!
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