WatchService Using ScheduledExecutorService Example

I was developing some code for the Java Certification Boot Camp project on Java.net where I wanted to demonstrate how to use the WatchService from JDK7 to monitor filesystem activity. I also wanted to demonstrate using it with an Executor.

As part of the process, I needed a graceful way to exit the program when the program completed. I thought that I would simply Google a solution, but I did not find one that met my needs.

So here is the use case I would like to have a WatchService running in its own thread and monitoring the filesystem. After a time period, I would like the service to shutdown gracefully.

I decided to use A ScheduledExecutorService which would start the WatchService using a Callable<V>, and another Runnable which was scheduled to shutdown the WatchService and the ScheduledExecutorService.

So here is how I did it.

WatchServiceImpl.java

---

Java Certification Boot Camp - Generics and Collections

Module 04 - Generics and Collections

Java Certification Boot Camp - Object Oriented Design Principles

Module 03 - Object-Oriented Design Principles

Java Certification Boot Camp - Advanced Class Design - Module 02

This is the second presentation for Java Certification Boot Camp to Java.net and to Scribd for anyone who is interested in the presentation. Module 02 - Advanced Class Design

Java Certification Boot Camp - Java Class Design - Module 01

I uploaded my first presentation for Java Certification Boot Camp to Java.net and to Scribd for anyone who is interested in the presentation. Module 01 - Java Class Design

Oracle Certified Professional Java SE 7 Programmer Boot Camp

We had our first meeting last night of the boot camp for the Greenville Java Users Group (GreenJUG) for Oracle Certified Professional Java SE 7 Programmer certification. This is based on the work we have done for the SCJP for Java SE 6 which was very successful. We have run three previous boot camps with great success. Although a number of people attend the boot camp, not very many take the exams. We do have a great success rate for those who attempt it: 11/11 (100%).  We hope to be able to continue the same streak going forward.

Last night we covered Chapter 10 - Development from the SCJP Sun Certified Programmer for Java 6 Exam 310-065 book. I have not found any published books on SE 7 certification so we are using this book in the interim. Additionally, we are adding material to cover the gaps including material from Preparation for Java Programmer Language Certification.

Over the next few weeks I will publish our code to the Java Boot Camp project on Java.net. I will also publish my slides with a CC license. All coding modules going forward will be done using Apache Maven and are developed on NetBeans. Current Java code in the bootcamp was developed with NetBeans, but are not Apache Maven projects.

Exam Tip

Here are some quick rules for code questions on the exam.

• Does the code compile?
• Does the code run?
• What is the output?

If you can answer these questions before looking at the answers, you have the code portion of the exam beat! Here is an example from last night. Please note that it is obfuscated for a reason, and does not represent good coding practices. So when you examine the code, see if you can answer the questions above. This will likely be harder than anything you can expect on an exam.

Oracle Certified Java Programmer Boot Camp Code Examples

Image via Wikipedia

I uploaded all of my code examples today for the free Oracle™ Certified Java™ Programmer Boot Camp that I do for the Greenville Java Users Group (GreenJUG).

You can find more information on the JUG site about the boot camp, and from the links below. The projects are NetBeans 6 files.

You need to still need to attend for the presentations! If I posted those, you wouldn't feel the need to come and participate.

Code Examples

• Lesson 1
• Lesson 2
• Lesson 3
• Lesson 4
• Lesson 5
• Lesson 6
• Lesson 7
• Lesson 8
• Lesson 9
• Lesson 10

Links

• Greenville Java Users Group (GreenJUG)
• Oracle™ Certified Java™ Programmer (SCJP) Boot Camp
• Example Projects and Software

Suggestions for IT Professionals in a Down Economy

I just read an article from Computer World about how to remain positive in a down economy. I found the article to be spot on.

The first item was going back to your roots and doing the things that attracted you to a career in IT. I agree. If you are not doing something you love now, go back and reflect on why. Perhaps it is learning something new, or fixing something old. Get the flame back.

The second item referred to social networking. I am on Linked-In, Twitter, Facebook, Plaxo, etc. I know a number of people who have made this their personal addictions. I have not become addicted to it, but I find a lot of value. The ability to connect with friends, colleagues (current and former), peers, and associates is truly satisfying. It can help you in many ways, as long as, you are careful not to post anything that you would not be proud to show your mother.

They mention getting out into the real world. I would agree. I recommend joining your local user groups (Java Users Group), and attend free conferences like the Southeast Linux Fest. These groups are your peers, and contacts to potential jobs. Conferences can enhance your technical skills, and allow you to meet like minded individuals. It also can expose you to new technologies to make your IT life better.

The article also mentions getting technical certifications. I could not agree more. Here again, your local technical user group may be able to help by offering courses, certification boot camps, or technical deep dives. You can also enhance your knowledge by offering to give talks. You will really learn how much of a subject matter expert you are based on the questions the attendees ask.

Sun™ Certified Java™ Programmer Boot Camp

The Greenville Java Users Group (GreenJUG) is conducting an ten (10) week boot camp to prepare its members for the CX-310-065 exam. It is a great opportunity to get a better understanding of Java™ and a obtain a valuable industry certification.

The code examples, books, and notes can be found on the Blue Lotus Software Sun™ Certified Java™ Programmer (SCJP) Boot Camp site. All of the code is Open Source Apache 2 licensed. The schedule for classes and final exam preparation are on the GreenJUG site.