Getting Started with Simple wso2 ESB EJB Mediator Sample

The EJB mediator calls an external Enterprise JavaBean(EJB) and stores the result in the message payload or in a message context property. Currently, this mediator supports EJB3 Stateless Session Beans and Stateful Session Beans.

WSO2 ESB EJB Mediator

The EJB mediator calls an external Enterprise JavaBean(EJB) and stores the result in the message payload or in a message context property. Currently, this mediator supports EJB3 Stateless Session Beans and Stateful Session Beans.

Getting Started with Simple Remote EJB 3.X Server Sample

This sample will give you a simple working experience with EJB client server . here I’m using netbeans as IDE and JBoss 5.1 as my EJB Container. and I created seperate client for Stateful an Stateless EJB sessions  in order to make easy the development .We'll create a ejb module project named EJBTestServer.

Getting Started with Simple RMI services

Writing your own RMI services can be a little difficult at first, so we'll start off with an example which isn't too ambitious.In this example, we have followed all the 6 steps to create and run the rmi application. The client application need only two files, remote interface and client application. In the rmi application, both client and server interacts with the remote interface. The client application invokes methods on the

JAVA Remote Method Invocation (RMI)

Remote method invocation allows applications to call object methods located remotely, sharing resources and processing load across systems. Unlike other systems for remote execution which require that only simple data types or defined structures be passed to and from methods, RMI allows any Java object type to be used - even if the client or server has never encountered it before. RMI allows both client and server to dynamically load new object types as required.

Study About Enterprise Java Beans (EJB) Introduction

Enterprise Java Beans (EJB) is a development architecture for building highly scalable and robust enterprise level applications to be deployed on J2EE compliant Application Server such as JBOSS, Web Logic etc.

A recent study by Java developer Raghu Kodali has shown that porting Sun's Java EE tutorial application RosterApp from EJB 2.1 to EJB 3.0 resulted in

WSO2 ESB Mediator

Mediators provide an easy way of extending the ESB functionalities. WSO2 ESB is based on the WSO2 Carbon platform, which uses OSGI as the underlying technology. It implies everything that runs inside the WSO2 ESB to be OSGI bundles.

WSO2 ESB Feed Inbound Endpoint

Atom 1.0

Atom is the name of an XML-based Web content and metadata syndication format, and an application-level protocol for publishing and editing Web resources belonging to periodically updated websites. All Atom feeds must be well-formed XML documents, and are identified with the application/atom+xml media type.

WSO2 ESB Feed Connector

Atom is the name of an XML-based Web content and metadata syndication format, and an application-level protocol for publishing and editing Web resources belonging to periodically updated websites. All Atom feeds must be well-formed XML documents, and are identified with the application/atom+xml media type.

Getting Started with Simple Apache Abdera Server

Apache Abdera provides an implementation of the IETF Atom Syndication Format and Atom Publishing Protocol standards (RFC's 4287 and 5023). In this blog we're going to walk through how to build an Atom Publishing Protocol service server sample using Abdera's concepts of Providers and Collection Adapters. If you remember your AtomPub basics, you'll recall that AtomPub services are organized in a hierarchical way such that we have:

Getting Started with Simple WSO2 ESB Custom Inbound Endpoint

WSO2 ESB supports several inbound endpoints, but there can be scenarios that require functionality not provided by the existing inbound endpoints. For example, you might need an inbound endpoint to connect to a certain back-end server or vendor specific protocol.

WSO2 ESB Inbound Endpoint

Inbound Endpoint is an endpoint which resides in server side of the ESB. Those are introduced to achieve  some of the main features like multi tenancy support for some protocols like JMS, by passing axis2 layer in  Inbound side,deploying and undeploying inbound endpoints without server restarting. 

 Basically there are two  behaviours introduced. Selection of the behaviour is done according to protocol.

• Polling behaviour
• Listening behaviour    
  

Getting Started with Simple WSO2 ESB Connectors

A WSO2 connector allows you to interact with a third-party product's functionality and data from your ESB message flow, enabling you to connect to and interact with the APIs of services such as Twitter, Salesforce, and JIRA. This means that if you have enabled the Twitter and Google Spreadsheet connectors in your ESB instance,

Development challanges

Error-1

java.lang.ClassFormatError: Illegal local variable table start_pc 39 in method org.apache.synapse.transport.passthru.PassThroughHttpSender.sendUsingOutputStream(Lorg/apache/axis2/context/MessageContext;)V

java.lang.ClassFormatError: Illegal local variable table length 81 in method org.apache.synapse.transport.passthru.PassThroughHttpSender.maintenanceShutdown(J)V

Solution
adding the JVM arg -XX:-UseSplitVerifier(in wso2server.sh/bat)
Ex:-     $JAVACMD \
    -Xbootclasspath/a:"$CARBON_XBOOTCLASSPATH" \
    -Xms256m -Xmx1024m -XX:MaxPermSize=256m \
    -XX:-UseSplitVerifier \

###############################################

Error-1
When we run load test on ESB server by default it will only allow 20 concurrent threads to send out so if we increase the size of the thread in synapse properties(//repository/conf/synapse.properties) we may encounter the error.

[CodeBlob (0x00007f3fc1051e10)]
Framesize: 0
BufferBlob (0x00007f3fc1051e10) used for StubRoutines (2)
#
# A fatal error has been detected by the Java Runtime Environment:
#
#  Internal Error (sharedRuntime.cpp:834), pid=4948, tid=139907131430656
#  fatal error: exception happened outside interpreter, nmethods and vtable stubs at pc 0x00007f3fc105436f
#
# JRE version: Java(TM) SE Runtime Environment (8.0_45-b14) (build 1.8.0_45-b14)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.45-b02 mixed mode linux-amd64 compressed oops)
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
# An error report file with more information is saved as:
# /home/rajjaz/Documents/ESB/wso2esb-5.0.0-RC/hs_err_pid4948.log
#
# If you would like to submit a bug report, please visit:
#   http://bugreport.java.com/bugreport/crash.jsp
#
Aborted (core dumped)


Solution

Increase the number based on the machine capacity

What is WSO2 Enterprise Service Bus (ESB)

An enterprise service bus (ESB) is a software architecture construct that enables communication among various applications. Instead of having to make each of your applications communicate directly with each other in all their various formats, each application simply communicates with the ESB, which handles transforming and routing the messages to their appropriate destinations.