Friday, 9 September 2011

Quartz Scheduler - Cannot instantiate type SimpleTrigger (JobDetail)

One of the projects that I will soon be working on will use the Quartz scheduler. This is a Java framework for scheduling tasks (or jobs). One of the problems I came across when trying write code using Quartz based on books and internet tutorials was that I came across two errors.


  1. Cannot instantiate type SimpleTrigger
  2. Cannot instantiate type JobDetail
After searching for a solution I found many forum posts describing the same problem. The only responses given were to ensure all the appropriate JAR files were added to the project build path/class path. For me though this didn't solve the problem.

After some probing I realised the problem I was having which basically made the majority of the tutorials and examples on the internet correct in theory but syntactically wrong and the code they contained useless to me. The problem is that I was using the latest version of Quartz 2.0 and this updates has significantly changed the API from all quartz 1.x versions (e.g. quartz 1.8).

So if you are using (or updating to) Quartz 2.0 and you find you have these problems I have three tips for you

  1. Familiarise yourself with all of the changes and new features of Quartz (click here)   
  2. Read and understand the source code available in the examples folder that comes with your quartz download
  3. Follow the official Quartz tutorial (click here) To learn how to use the new API
Hope this helps

Mayo

9 comments:

  1. i was facing the same problem, and your blog really helped me .... thanks

    ReplyDelete
  2. Hey,
    Thanks a lot. Actually the very first point makes it very clear. Just goto the page that is linked in 1st point and do exactly as it says. Just include your quartz.all.jar in your build path and you will be fine to work with your application.

    Thanks once again.

    ReplyDelete
  3. Thnx alot. This really helped me.

    ReplyDelete
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    Trang tham khảo : Giá thạch anh vụn

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  8. ***
    Bài viết của Chủ thớt rất hay, thank anh đã share.
    Thông tin thêm : Thiềm thừ

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