Sentiment analysis is done by using posts and comments posted by users of a platform. The sentiment analysis approach is using to check which are the positive posts, that can be recommended for a user and to identify which are the negative posts. For this, as the first step data preprocessing techniques should be used to construct the data. Then feature extraction and training a model using the machine learning algorithm. Then check the positivity and negativity of the posts.

For the research paper of the analysis:

With the development of Information Technology, various types of texts are sharing and communicating. But there is no analytical way to share information through online communities. Even if technology is developed to the current state, there is no online platform to share knowledge and information with classifying according to the…

  • If we evaluate the JSON path as below we will receive the following error.
<arg evaluator="json" expression="$ctx:Error"/>

The error which we can receive

ERROR {org.apache.synapse.deployers.TemplateDeployer} -  Template Deployment from the file : C:\wso2\wso2ob-ei-6.4.0\wso2\tmp\carbonapps\-1234\\test_app_1.0.0\test_app-1.0.0.xml : Failed.
com.jayway.jsonpath.InvalidPathException: Illegal character at position 1 expected '.' or '[
at com.jayway.jsonpath.internal.path.PathCompiler.readContextToken(
at com.jayway.jsonpath.internal.path.PathCompiler.compile(
at com.jayway.jsonpath.internal.path.PathCompiler.compile(
  • JSON path is evaluated from the “com.jayway.jsonpath.json-path_2.2.0” library and this library has been updated with the latest EI versions. After this update, it only supports the JSON dot notation and for the bracket notations
  • To overcome this issue you can evaluate the above using the XML as the evaluator.
<arg evaluator="xml" expression="$ctx:Error"/>
  • Here I am trying to pass a value as a system property when the server is starting. I pass this property as I added it to file as below.””\
  • And I start the WSO2 server passing the property as below.
  • Following is the sample API of WSO2 ESB which I used to log the passed system property.
<api xmlns="" name="Test" context="/test">
<resource methods="GET">
<log level="custom">
<property name="System_Property" expression="get-property('system', '')"/>
Logged system property


WSO2 ESB or EI and Developer Studio (EI Tooling)


The Data Mapper mediator is a data mapping solution that can be integrated into a mediation sequence. It converts and transforms one data format to another, or changes the structure of the data in a message.

Create deployable artifacts using developer studio

  • In WSO2 EI Tooling, I…

This is related to WSO2 Identity Server 5.3.0.

The WSDLs of admin services are hidden by default. To observe the admin services we need to follow below steps.

  • Navigate to <IS_HOME>/repository/conf directory and open the carbon.xml file.
  • Set the <HideAdminServiceWSDLs> element into false as below. By default it has set to true.
  • Go to the <IS_HOME>/bin directory…
  • We can set the wait_timeout variable, for a session or globally.
  • If we set the wait_timeout variable for a session, it will valid only for a particular session. But when we set the wait_timeout variable globally it will valid for all the sessions.

To run these commands, first we need…

Dilsi Chandrasena

Senior Software Engineer at WSO2

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store