How to Change Git Commit

Change Git Commit Message

During one of my developer testing, I have changed my machine date with additional one month. After Testing the fix I committed the code. But then realised git use my machine date as committer date. Now when I check the git repo, my commit with date change show as the latest commit.

How to fix that.

Passing END_User_Name to as customized header to backend

Overview

This blog post describes how we can pass end user username to customized header.

Change email address for user in WSO2 Identity Server

Overview

Sometimes users need to log in using their email address as username but they need to change their email address and log in user new email address. With WSO2 identity Server 5.0.0 there is no direct way to update email address when you use email address as username.  Because chaging the username (uid) in WSO2 IS 5.0.0 is not recommended due to several limitations. This blog post provide workaround for change email address and log in using your new email address.

Use Account Lock feature to block user token generation

Overview

In this blog I will describe how we can block user getting token. So I am using api manager 1.6 with installing IS 4.6.0 features.

JMS performance tuning with WSO2 ESB

Overview

WSO2 ESB can be configured as both a producer and consumer for a JMS broker[1]. As an example ESB can listen to JMS queue(Apache ActiveMQ) consume messages and send them to back end service. It can also be act as JMS producer which can send messages to JMS queue. In this post I am discussing about JMS performance tuning with WSO2 ESB. Performance of JMS service over HTTP can be reduced due to messages are being served by a single threaded JMS listener. There are few ways to address that. These are the steps to tune Performance. 

WSO2 ESB caching in Tenants

Overview

We use registry to store resources which will be used by artifacts deployed in WSO2 Products .This post describes some issues when enable or disable caching in WSO2 ESB.

Rest Service with ODE process

Overview

Web services can be two types as SOAP or REST. BPEL processes communicate using soap messages.This post describes how we can call Rest service within our BPEL process.

Develop Simple BPEL Process

Overview

This post describes how we can develop simple BPEL process using WSO2 Developer studio and deploy and run it on WSO2 BPS server. Process will take your name as input and output with "Hello: " and your name.

Resizing images for Email

Overview 

Re sizing or reducing the image size will be helpful for us in cases like

1. Sending set of images via email .
2. Portable drive space for set of bulk images

Most of email servers have limitations with maximum size of attachments. You can upload and provide the link but for some privacy reasons you prefer to send photos via email.This post provides just two commands for reduce size of set of bulk images.

Load testing with Apache Bench

Overview

We use load testing to check how our application behavior when large number of requests concurrently access the application. This post is about how to do a simple load test with Apache Bench.

How to publish Mock Service with SoapUI

Overview

SoapUI is well known tool for manipulating different tests with web services and rest services. This post will discuss about mock service and applicability of mock services in your service based projects.

What is bpel

Overview

This post describe some basic concepts of BPEL which is a XML based language used to model business processes.

Simple MapReduce Program for Hadoop

Overview

Previous post we went through basics of big data processing and Hadoop. This post I describe some basic map reduce program structure. Here I have used example of counting words in large number of books. I have configured a two node cluster with distributed file system. Here we are using three classes as,

1. Mapper class 
2. Reducer Class 
3. Main words Count Class 

Assume I have 10 documents having only words “hello” and “world”. Documents will be shared by two nodes. How much documents for each node will be decide by Hadoop framework.

Database level Pagination with JPA

Overview

Pagination is a presentation technique used to show large amount of data set in client UI side as set of pages with set of options like next,previous,first last etc. 

Pacemaker, DRBD Active-Passive Cluster

Overview

Active Passive cluster consists of two nodes: active node and passive node. Active passive cluster ensures constant service of a certain application keeping redundant nodes to back up system in the event of a failure. When the active node goes down one of the backup nodes takes the responsibility and runs those services. In the process of fail over, the services are restarting on another node immediately without administration intervention.

Big Data processing with Apache Hadoop

Overview

Earlier software applications have been developed to run on single computer. Some examples are calculators, word processing packages, drawing applications etc. With the introduction of client server architecture vast amount of software systems were developed with databases. Most of web applications, business systems are built databases and concurrency, transaction handling are some new terms introduced with the architecture. Now world has moved to new computer era with concepts of high performance computing.

Apache Load balancing with HAProxy

Overview

HAProxy is an open source load balancing software run on Linux. It will divide the load which may be web page or database query requests upon slave servers from the master. Therefore usual Linux machine can be configured as a load balance without any hardware load balancing capabilities.

Useful Maven Commands

Overview

Previous post I have described some basic concepts of Apache Maven. Here I have included some useful commands need for day to day maven operations.

What is Maven

Overview

Developing a software  system doesn't means just writing codes. It may be set of code lines for simple program but when we go for large application development we have to think beyond that. When developing java applications some important tasks have to considered.

What is Computer Cluster

Computer cluster is a collection of computers connected as a grid to perform special tasks. Rather than using one high performed computer, collection of computers so called cluster provides considerable advantages through high availability and performance. Computer cluster can be specified according to different criteria. Here is a summary of classification of clusters.