Remote debugging for Tomcat and IntellJ on Max OS X

IntellJ supports remote debugging for Tomcat. It is really convenient for debugging. This entry shows how to adopt remote debugging with Tomcat and IntellJ.

My dev environment

• Max OS X 10.9.2
• Java 1.8.0
• Tomcat 8.0.3

Set up

Tomcat

1. Create a new file called <Tomcat install directory>/bin/setenv.sh. (This file will be automatically read by catalina.sh)
2. Add the following content to setenv.sh. 8080 is a port number for Tomcat. Please specify for your tomcat.
• CATALINA_OPTS="-agentlib:jdwp=transport=dt_socket,address=8080,server=y,suspend=n"
3. Start Tomcat normally using startup.sh.

IntellJ

1. Select "Run -> Edit Configuration" then "Run/Configuration" screen is open.
2. Specify "Name" like "Tomcat".
3. Specify "Port", which is the same number as Tomcat's port numer

Debug

1. If you want to start debugging on IntellJ, just select "Run -> debug 'Tomcat'". 
2. If IntellJ shows a message like below, you are already connected.
• Connected to the target VM, address: 'localhost:8080', transport: 'socket'
3. Now you can debug. Please refer here for more detail about debugging by IntellJ.

Apache Lucene: Then and Now, Java User Group meetup at Twitter HQ

Meetup.com - Apache Lucene: Then and Now

This time, Doug Cutting (@cutting) talked about the history of Apache Lucene and how Apache Lucene is used for the implementation of Internet search engines and local, single-site searching in major tech companies like Linkedin or Twitter. He also mentioned this project is integrated with Hadoop and still evolving.

Doug Cutting (@cutting) is the founder of numerous successful open source projects, including Lucene, Nutch, Avro, and Hadoop. Doug joined Cloudera in 2009 from Yahoo!, where he was a key member of the team that built and deployed a production Hadoop storage and analysis cluster for mission-critical business analytics. Doug holds a Bachelor’s degree from Stanford University and sits on the Board of the Apache Software Foundation. (cited from Meetup.com) 

His talk is based on the following blog entries.

• Cloudera Search: The Newest Hadoop Framework for CDH Users and Developers
• The Blur Project: Marrying Hadoop with Lucene

As you see, his roles in his company (Cloudara) is the implementation of the new open source project, Blur.

Blur is an Apache Incubator project that provides distributed search functionality on top of Apache Hadoop, Apache Lucene, Apache ZooKeeper, and Apache Thrift. When I started building Blur three years ago, there wasn’t a search solution that had a solid integration with the Hadoop ecosystem. Our initial needs were to be able to index our data using MapReduce, store indexes in HDFS, and serve those indexes from clusters of commodity servers while remaining fault tolerant. Blur was built specifically for Hadoop — taking scalability, redundancy, and performance into consideration from the very start — while leveraging all the great features that already exist in the Hadoop stack. (cited from blog.cloudera.com)

And Cloudera is providing a better way for non-programming users interact with Hadoop data.

In the context of our platform, CDH (Cloudera’s Distribution including Apache Hadoop), Cloudera Search is another framework much like MapReduce and Cloudera Impala. It’s another way for users to interact with Hadoop data and for developers to build Hadoop applications. Each framework in our platform is designed to cater to different families of applications and users (cited from blog.cloudera.com)

 See Cloudera blog for more details.

It seems that there are meetup of Java user group in SF once or twice a month. I am planning to continue joining meetup.

How to fix an error "Unable to find a $JAVA_HOME at “/usr”, continuing with system-provided Java"

Somehow, I have got this error whenever I run Java command:

$java -version
Unable to find a $JAVA_HOME at "/usr", continuing with system-provided Java...
java version "1.7.0_25"
Java(TM) SE Runtime Environment (build 1.7.0_25-b15)
Java HotSpot(TM) 64-Bit Server VM (build 23.25-b01, mixed mode)

I found the same error as my case at the stackoverflow.

Unable to find a $JAVA_HOME at “/usr”, continuing with system-provided Java

This happens when $JAVA_HOME is not set correctly. In my case, the following works form me.

export JAVA_HOME="$(/usr/libexec/java_home)"

My environment is as follows:

• OS X 10.9
• Java 1.7.0_25 (installed by brew)

Ant 1.8 "warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds"

I installed Ant 1.8 and build Java applications with Ant. Then, I found the following message:

warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds

You can find a good explanation of this warning with following link:

http://ant.1045680.n5.nabble.com/warning-includeantruntime-was-not-set-td2639463.html

There were incompatible change on Ant version 1.8. So, you may find the same message if you build old ant file with Ant 1.8.

Please just add includeantruntime="false" to javac task.

compile problem because of an expired debug certificate

When I was compiling my Android app, I couldn't do it. I found this message in Problem view.

Error generating final archive: Debug certificate expired on XXX

I found same problem in android web site. According to the site, the Android build tools local debug key but it is already expired. To fix this problem, I had to regenerate my debug key.

Here is the step.

1. delete the debug keystore/key already generated by the Android build tools. Specifically, delete the debug.keystore file. On Linux/Mac OSX, the file is stored in~/.android. On Windows XP, the file is stored in C:\Documents and Settings\<user>\.android. On Windows Vista, the file is stored in C:\Users\<user>\.android
2. generate new debug keysore file with this command: keytool -genkey -v -keystore <PATH_TO_FILE>/debug.keystore -alias androiddebugkey -keyalg RSA -validity 10000 -dname "CN=Android Debug,O=Android,C=US"

Note: <PATH_TO_FILE> is a path to the debug keystore file. Please set appropriate path for your environment.