How to remove a system property in java?

[pengwg]

Hi!

Can some tell me the easiest way to remove a system property. I tried with
System.setProperty("myProperty", null);
It didn't work.

Regards,
Wei

[Jon Skeet]

What do you mean by "remove" in this case? What is end effect you want
to have? Just that System.getProperty will return null?

--
Jon Skeet - <sk...@pobox.com>
http://www.pobox.com/~skeet/
If replying to the group, please do not mail me too

[Gordon Beaton]

Properties extends Hashtable, so
System.getProperties().remove("myProperty") might be what you are
looking for.

Keep in mind though that many of the properties are only informative,
so changing or removing them doesn't affect anything but the set of
properties itself.

/gordon

--
[ do not send me private copies of your followups ]
g o r d o n . b e a t o n @ e r i c s s o n . c o m

[pengwg]

Yes, exactly. The reason is that after I modify a system property I
have to set it back to its original state. If this original state is
null (not defined), I get trouble. The setProperty() throws always an
exception. E.g:

String oldPropery = System.getProperty("somGlobalPropery");
System.setProeprty("somGlobalPropery", "myValue");
// do somthing
......
// set it back
System.setProeprty("somGlobalPropery", oldProperty); // fails if
oldProperty is null

Wei

Jon Skeet <sk...@pobox.com> wrote in message news:<MPG.1638b4a36...@mrmog.peramon.com>...

[Jon Skeet]

pengwg <wei-gu...@sap.com> wrote:
> Yes, exactly. The reason is that after I modify a system property I
> have to set it back to its original state. If this original state is
> null (not defined), I get trouble. The setProperty() throws always an
> exception. E.g:
>
> String oldPropery = System.getProperty("somGlobalPropery");
> System.setProeprty("somGlobalPropery", "myValue");
> // do somthing
> ......
> // set it back
> System.setProeprty("somGlobalPropery", oldProperty); // fails if
> oldProperty is null

Right. What I suggest you do is use System.setProperties() instead -
when you want to make a change, do something like:

Properties previousProps = System.getProperties();
Properties newProps = new Properties (previousProps);

newProps.setProperty ("foo", "bar");
System.setProperties (newProps);

then later:

System.setProperties (previousProps);

Note that you'll get in trouble with this if you do this in different
places in an overlapping way.

[yasmi...@gmail.com]

You can use:

System.clearProperty("myProperty");

"myProperty" being the key.