November 13, 2014

Remote Debugging WSO2 ESB with IntellijIdea and Eclipse

This post assumes you are familiar with debugging concepts. The remote debugging will be explained using WSO2 ESB product.

What happens in remote debugging is that the debugging information of a running application is communicated with an IDE that has the source of the application. The application is not running from the source, and thus the term "remote" debugging. Similar to any normal debug scenario, where you would be running the application in debug mode from the IDE, you can have breakpoints, watch expressions, etc.

Read more about how remote debugging works in JVM at [1].

Let's proceed on how to debug WSO2 ESB.

Setup the Source for Debugging WSO2 ESB

There are a number of components in WSO2 stack that contribute to the complete WSO2-ESB product. Some of these components are : wso2-synapse, carbon-mediation, wso2-axis2-transport, carbon4-kernel, etc. You can download source of all these components at

Decide on the component(s) you need to debug, and import them to your preferred IDE (Eclipse or IntellijIdea). To do this :
  1. Clone the required component from the git repository : git clone <repository_url>
  2. Build the component : mvn clean install or mvn clean install -Dmaven.test.skip=true (to skip tests)
  3. To setup as an IDE project : mvn idea:idea (for IntellijIdea) or mvn eclipse:eclipse (for Eclipse)
  4. Add breakpoints as needed
  5. If debugging multiple components, 
    • Eclipse : Import as project to the same workspace and add breakpoints
    • Idea : Import as module to the same window and add breakpoints
    • Optionally, at the time of debug, when debugging takes you to the .class files, you can attach the relevant components as sources with "attach source" option and continue.
Note : 
If you want to debug message flow on ESB, add a breakpoint to receive(org.apache.axis2.context.MessageContext mc) method in org.apache.synapse.core.axis2.ProxyServiceMessageReceiver class in wso2-synapse. This is the start point to the message flow on ESB.

Remote Debugging WSO2-ESB

Step 1 : Start WSO2-ESB in debug mode

$ sh bin/ debug 5005
Please start the remote debugging client to continue...
JAVA_HOME environment variable is set to /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
CARBON_HOME environment variable is set to /Users/maheeka/wso2esb-4.8.1
Listening for transport dt_socket at address: 5005

We have started the ESB in debug mode, and it listens now on port 5005 for a remote debugging client. 

Step 2 : Start Remote Debugging Client (IDE)

  1. Run > Edit Configurations
  2. On the left panel, click on "+" and add a new Remote Configurations. Notice the port to be same as you give when starting ESB.
  3. Then Run > Debug 'wso2-synapse' to start the listener
  4. The application will now run as normal and stop at the breakpoints you have added

  1. Run > Debug Configurations
  2. Add a new Remote Java Application Configuration. Notice the port number to be same as you give when starting ESB.
  3. Click on Debug to start debugging 

November 10, 2014

Building WSO2 ESB 4.8.1 from source in OSX

WSO2 products are all built on top of WSO2 Carbon Kernel. This is the common ground for all products. Turing is the platform release name for WSO2 Carbon 4.2.0 and WSO2 ESB 4.8.1 is based on turing. Not all products of the WSO2 platform does not get released at the same time. Therefore, these products are released in chunks. ESB 4.8.1 comes under chunk 7 of the turing platform. Refer the release matrix to get more info on this [2].
Prerequisites : 
1. Install Java 1.6 and Maven 3
       If you have only 1.7 installed, you will have to install 1.6 on OSX. Unfortunately, there is no direct installation for 1.6. But this sorted out for me  since jdk 1.6 was automatically installed when I installed IntellijIdea
       At the moment, all WSO2 products are compiled on Java 1.6 and is supported up to 1.7. This is why we need to build the source on 1.6.
2. Checkout Source (Orbit, Kernel, Platform)

Building the Source : 

Start building in order Orbit > Kernel > Platform (chunk 07) repos respectively.

To build ESB 4.8.1, you need to build wso2carbon-platform/product-releases/chunk-07 as Platform in above.

The distribution will be created in :


When building, since it will take a lot of time, and to avoid unit test failures from building the product, skip unit tests when building.

mvn clean install -Dmaven.test.skip=true

Build ESB only :

If you need to build only ESB, build at wso2carbon-platform/products/esb with mvn clean install -Dmaven.test.skip=true

Another option is to comment out other product modules in platform/trunk/pom.xml and rebuilding in Orbit > Kernel > Platform in order.

Encountered Errors : 
  1. WSS4 maven install fails > You need to compile in Java 1.6
  2. [WARNING] Error injecting: org.apache.maven.reporting.exec.DefaultMavenReportExecutor > Set maven-site plugin version to 3.3 in all places [4]
Environment :