FIXING com.sun.tools.javac.Main IS NOT ON THE CLASSPATH APACHE ANT COMPILATION ERROR

A few days ago I was setting my development environment up and it involved executing some Apache Ant tasks. I had installed latest Java 7, jdk1.7.0_80 to be exact and Ant 1.8.4, required by the project.

Attempted to compile it and got this output:

C:\Users......\src>ant
Unable to locate tools.jar. Expected to find it in C:\Program Files\Java\jdk1.7.0_80\lib\tools.jar

...

BUILD FAILED
C:\Users\......\build.xml:xxx: The following error occurred while executing this line: .......:
The following error occurred while executing .......: Unable to find a javac compiler;
com.sun.tools.javac.Main is not on the classpath.
Perhaps JAVA_HOME does not point to the JDK.
It is currently set to "C:\Program Files\Java\jdk1.7.0_80"

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TROUBLESHOOTING CPU SPIKES IN JAVA APPLICATIONS

Possible causes of high CPU usage in Java apps might be related to:

  • Garbage Collector (GC) executing Major or Full collections too frequently without freeing much memory as a result of a memory leak in one of the applications served by the servlet container or a leak in the servlet container itself.
  • GC often executing Major or Full collections (similar to previous suggestion) because in fact, the application needs more memory.
  • Issues with the application like resource contention, long running jobs, expensive computation, …

The intention of this entry is to document a simple process to troubleshoot high CPU usage in Java apps once it has been observed that it’s not related to GC.

1) FIND THE JVM PROCESS

ps aux | grep java
tomcat   26551  128 30.9 3946348 1215360 ?     Sl   13:43  26:21 /usr/java/latest/bin/java ........ org.apache.catalina.startup.Bootstrap start

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TECH.ASIMIO.NET = AWS S3 + JEKYLL + JENKINS

Creating a blog was in my TODO list for too long, being too ambitious prevented it me from just getting it up. WordPress or Drupal + phpCAS or Java-based blog/CMS + Jasig CAS for Single Sign On between the blog + Asimio.net; it was too complex and time-consuming.

Earlier this year I read Soft Skills: The software developer’s life manual which I found it to be a really interesting book and that was it, I was decided to start a blog, but took a different route than what was suggested, it had to be simple and fun where I would learn something new in the process and after a day of quick research, I decided it to use Jekyll to generate a static blog and hosted it on Amazon S3 since I’m already using a couple of AWS services with Asimio.net.

In this post I’ll detail how to accomplish this and optionally, use Jenkins to implement a Continuous Deployment approach to automatically deploy the blog when new posts become available. It will also serve me as a short how to guide in case I decide to create a static site again.

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SIDE PROJECT

Asimio.net is a side project I have been working on for a few years now to catch up or play with technology that I don’t necessarily use as part of my daily job.

It’s a rental property information services provider that allows to search for vacant properties and registered users to list their properties, upload photos and save searches.

Asimio.net's Architecture

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