NullPointException about tomcat-redis-session-manager HOT 10 CLOSED

I don't see any reason there could possible be an NPE on that line. What is the original value and the new value? If you look at that line of code it seems impossible to come up with a way that you could get an NPE. At least, assuming it isn't getting thrown by and equals() implementation or something like that.

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original value is null, new value is an instance of MenuItem. I have no idea either. Pretty weird.

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Could you step through in a debugger by any chance and see exactly what
expression is triggering the NPE?

On Fri, Oct 12, 2012 at 10:56 AM, ajstokar [email protected] wrote:

original value is null, new value is an instance of MenuItem. I have no
idea either. Pretty weird.

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if ( value == null && oldValue != null
|| oldValue == null && value != null
|| !value.getClass().isInstance(oldValue)
|| !value.equals(oldValue) )

So if value AND oldValue are both null, the 3rd or statement will run and throw the exception. I think you need one more check if both of these are null, then just skip the if statement.

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Ah yes, something didn't feel entirely right about that, but somehow I
missed that.

On Fri, Oct 12, 2012 at 11:21 AM, ajstokar [email protected] wrote:

if ( value == null && oldValue != null
|| oldValue == null && value != null
|| !value.getClass().isInstance(oldValue)
|| !value.equals(oldValue) )

So if value AND oldValue are both null, the 3rd or statement will run and
throw the exception. I think you need one more check if both of these are
null, then just skip the if statement.

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Actually, you should probably still update the changeAttributes hash in this case. If I do setAttribute(key,null), I would expect it to behave the same as removeAttribute(key), right?

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If the old value is null as well, then nothing's changed right? Presumable
someone could argue about whether or not there's a difference between not
having the key and having the key be null, but I don't think we need to
worry about that unless someone has a reason to do so.

On Fri, Oct 12, 2012 at 11:25 AM, ajstokar [email protected] wrote:

Actually, you should probably still update the changeAttributes hash in
this case. If I do setAttribute(key,null), I would expect it to behave the
same as removeAttribute(key), right?

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/13#issuecomment-9379994.

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BTW, I have a new build, but could you test it and ensure it works for you
before I release it? (I'm not set up right now to run Tomcat)

JAR: http://cl.ly/0K1L2E2i3u0Z

On Fri, Oct 12, 2012 at 11:27 AM, James Coleman [email protected] wrote:

If the old value is null as well, then nothing's changed right? Presumable
someone could argue about whether or not there's a difference between not
having the key and having the key be null, but I don't think we need to
worry about that unless someone has a reason to do so.

On Fri, Oct 12, 2012 at 11:25 AM, ajstokar [email protected]:

Actually, you should probably still update the changeAttributes hash in
this case. If I do setAttribute(key,null), I would expect it to behave the
same as removeAttribute(key), right?

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/13#issuecomment-9379994.

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Works! Thanks for the quick fix.

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All right. I'll release the official fix sometime this weekend.

On Fri, Oct 12, 2012 at 11:32 AM, ajstokar [email protected] wrote:

Works! Thanks for the quick fix.

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Reply to this email directly or view it on GitHubhttps://github.com//issues/13#issuecomment-9380213.

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