quartz-scheduler

I already asked a separate question on how to create time triggered event in Java . I was introduced to Quartz. At the same time, I also google it online, and people are saying cron in Unix is a neat solution. Which one is better? What's the cons and pros? Some specification of the system: * Unix OS * program written in Java * I have a task queue with 1000+ entries, for each timestamp, up to 500 tasks might be triggered. Using cron seems to add another entry point into your application, while Quartz would integrate into it. So you would be forced to deal with some inter-process communication

I'm running my Jobs using Quartz with a cron expression every 50 seconds: Cron_Expression = "0/50 * * * * ?" What happens is that my job runs at the seconds: 50, 60, 50, 60,... and not every 50 seconds! and does not run at the second "0". What is the right cron expression every 50 seconds starting at 0? The '/' syntax specifies the increment during the period and not a repeat interval. Admittedly a subtle and confusing difference. In this case there is only one available increment (50 seconds) during the 1 minute period. The first number specifies the value to start with, in this case 0.

I am trying to run the sample helloworld program for quartz scheduling given on roseindi.net http://www.roseindia.net/quartz/quartz-scheduler-tutorial.shtml I have both the classes given there exactly similar setup in my java projecy with quartz version 1.6 - all.jar in the project library. When I try to run the application I get the following Exception Exception in thread "main" java.lang.NoClassDefFoundError: javax/transaction/UserTransaction at org.quartz.impl.StdSchedulerFactory.instantiate(StdSchedulerFactory.java:1104) at org.quartz.impl.StdSchedulerFactory.getScheduler

I have a quartz job in grails, that needs to be executed in every 5s, but I need this sequentially. In some situations the execution of the job exceeds this 5s, in this case I dont't want to be executed while the previouse exection is not finished. How to configure this in grails? (Of course the whole magic could be done with a static volatile flag, but is not a very elegant way to do this) (Also how can I configure for the job to be singleton?) thx Assuming that you're using the grails quartz plugin, you should just be able to set the concurrent property of your job class to false . From the

I have a class "Applier" which implement Job . Means class "Applier" is one of instance of Quartz Job. My requirement is to control number of instance of "Applier" execute at a time. Means i want to make limit like at a time maximum 5 instance of "Applier" execute. If 6th instance of "Applier" come and 5 instance already executing than it must have to wait until one of the instance of "Applier" completed. Is there any wait/notify type mechanism in Quartz Scheduler. Means if 6th instance of Job try to run and 5 instance of already executing than 6th instance must have to wait and notify after

I have a problem. Quartz keeps putting its log on all my log files. Can I redirect Quart's log to a separate file? Here is my logback.xml : <configuration debug="false"> <appender name="hcmut.cse.virtuallab.request" class="ch.qos.logback.core.FileAppender"> <file>log/hcmut.cse.virtuallab.request.log</file> <encoder> <pattern>%date %level [%thread] %logger [%file:%line] %msg%n</pattern> </encoder> </appender> <appender name="hcmut.cse.virtuallab.timer" class="ch.qos.logback.core.FileAppender"> <file>log/hcmut.cse.virtuallab.timer.log</file> <encoder> <pattern>%date %level [%thread] %logger [