John Mercier

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since Nov 23, 2006
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Recent posts by John Mercier

Thanks for the info. I'm not sure we even considered how the size affects things I think before we switched to uuid it was a long. The concern with uuid is actually in a different part of the system which uses a dynamodb table with documents indexed in elasticsearch. I think size should be a concern but the argument being made is to append a timestamp to the uuid which would be worse for a few reasons. I'm just trying to argue that uuid is more that sufficient for our use case and there are no gains in appending a timestamp. Thanks for the help!
2 weeks ago
I am working on an enterprise system that streams data using aws and kafka. We are using UUID for the primary key of data saved in the database and UUID for other parts of the system. Should there be any concern with collisions when using random UUID?

I ask this because one of our "architects" wants to change everything over the concern that uuid will have collisions. In my own research I have found this:

"For example, the number of random version-4 UUIDs which need to be generated in order to have a 50% probability of at least one collision is 2.71 quintillion"

Are there any real problems with using a random UUID in java? Should my team be concern?
2 weeks ago
Specifically is removeIf, replaceAll, or forEach covered in Collection implementations. Is the new Map api covered? Are the new "of" methods covered?
Looking at the exam topics I don't see java collections at all. Are there any changes to java collections that are covered in the exam?

exam topics
I have been working for a while on graph-dsl. It started with the goal of learning gitflow, versioning, testing, api design and continuous delivery. I think things have gone pretty well so far but it is not quite ready for a 1.0 release. Any input is welcome.
1 year ago
Is it possible to use @Delegate inside a trait. I have this project that has an Edge class.and DirectedEdge class. The equals methods need to be different. in EdgeMapPlugin I want to apply LinkedHashMap using withTraits so any edge can be used like a Map. The problem is equals will get changed as well. I was wondering if it is possible to use a @Delegate in a trait to apply LinkedHashMap but still use the super.equals?
2 years ago
You could try using eachWithIndex.

4 years ago
Is there a standard way to run tomcat on port 80 in Redhat Enterpise Linux? We currently have a iptables rule that redirects 80 to port 8080. The service can be opened from port 80 and 8080. Somehow this is more secure... Is this common? Is there a better way? Could the tomcat user be given permission to open port 80 instead?
4 years ago
I figured out the problem. In the end it was an issue with the way the network was setup.
4 years ago

I'm working on a project that uses spring-security-core- I recently haven't been able to download the plugin which is causing problems running the project.

To see if there was anything wrong with my project I created a test project.

and added

I am still having the same error

Could there be something wrong with the grailsPlugins() repository?
4 years ago
Virtual box is free but there is also a set of free images here If you are not familiar with Linux I would go with something like fedora or ubuntu. You still need to figure out how to install java and push your applications to the vms.
4 years ago
Hello, I recently worked on some code to recover an md5 in case a process crashes.

Any thoughts or comments?
This is because * is 0 or more. at position 6 there are 0 digits.
A junior developer position should not require experience. If you are already in the company I would suggest asking them if you could work part time as a developer until they are comfortable with you. If not I suggest looking into other companies in the area.

If you already have a certificate start getting familiar with other tools. IDEs, svn, git. Try setting up your own project on github while applying for other jobs. Don't give up on starting your career as a java developer.
I would look into setting up virtual box on your machine. You could create 3 images for the os of your choice and have them running at the same time. In virtual box you can setup a network between the machines and test out your applications all from your machine.
4 years ago