Creating a set of scheduled tasks, is this a good approach?

I have several scheduled tasks I have to develop.

Some of them will take up to 2 hours.

I need to write those in Java.

I am pretty new to this, Should I write those tasks under Tomcat?

How do I trigger them to start, (I assume each task will have a URL, right?)

Can I run tasks under TOMCAT which take 2 hours?

Is it the right way, or is there a better one.

and, last one, Will a new JVM be created each time I start a task, or will they be compiled only once and the JVM will stay up for ever?