68 articles
Now, most Java developers are busy mitigating Apache Log4j2 Vulnerability (CVE-2021-44228 and CVE-2021-45046). Applications are literally on fire. Here, I have created a sample project using Spring Boot and Log4j2 to demonstrate (Video Demo) the vulnerability and possible remediation. Please take a
Windows Subsystem for Linux (WSL) is an awesome feature of Windows 10. No more VMware or Oracle VirtualBox is required to run Linux on Windows. WSL is faster and less resource consuming, zero or less configuration compared to any other traditional Virtual Machines (VM). Installation and setup of Lin
If you are running Ubuntu on Windows WSL (Windows Subsystem for Linux) and wondering how to change hostname permanently then follow all steps mentioned below. Once hostname is changed, if you get "unable to resolve host <hostname>: Name or service not known" then follow the step #4 for the fix. Vi
"No News is Good News". That is what I used to get from Identity Guard®. But yesterday, I got email & sms notification "Alert: Your Login Credentials Have Been Exposed Online". And partial password shared in that notification is actually matching with my credentials. So, mine got exposed. Check your
Techsmith Camtasia 2020 introduces a video template. Now, we can create a video template and share it with the team to build consistent and professional videos quickly. This is really great. But like many Camtasia users, I also terribly miss the feature to add Quick Properties to the custom groups,
Andy learning to code. He seemed a little worried. Mike happens to stop by. "You seem worried. What’s on your mind?" asked Mike. "Well Mike, I’ve been trying to understand exception handling. But I can’t seem to wrap my head around it." answered Andy. Mike laughed and said "I see. Come with me.
Is node-gyp (Node.js native addon build tool) failing during yarn install or npm install? If your macOS got upgraded to Catalina (10.15) recently, then you will find the fix right here.
4,153,406 hits in single day! Sounds like a really big number for many of us. I was surprised when I noticed this in Production ELK for the first time. I didn't expect that many hits for an application with only 5 microservices. That too for a Beta application with a handful (~2k) of users. It wil
Pandemic! Human race is now at stake. Flatten the curve. Whole world is running after this epidemic curve. Why it so important? [https://commons.wikimedia.org/wiki/File:20200403_Flatten_the_curve_animated_GIF.gif#/media/File:20200403_Flatten_the_curve_animated_GIF.gif] By RCraig09 [//commons.wik
Sometimes I feel, kids do this just to irritate us. Or may be, we always have a prioritized list of problems in our subconscious mind. When we solve the top one, the next one pops up and gets highlighted. It is indeed never ending. Few extra hours of running TV will hardly make any difference in m
Outside of home COVID-19. Inside at home COVID-16. Whole world is fighting against COVID-19. But for COVID-16, I am all alone. I am tired of saying "please stay away from the screen". So thought of this concept project to avoid brain infection at home. By the way, I call two of my kids (age 1 and 6
Live feed forging formed the base of the Professor's "Paris Plan" to rescue Lisbon from police custody in Money Heist (Season 4). A smart attacker always makes or covers up his tracks by forging something. Cyber-attacks inflict loss of reputation and wealth worth millions.
Security is always an essential aspect of any web application. HTTP security headers play an important role to tighten up the security of web application. It acts as an additional security layer to defend many common vulnerabilities and attacks like clickjacking, cross-site scripting (XSS), cross-s
ESP8266 based Internet enabled (IOT) smoke and fire alarm to send SMS notification (Twilio) and to trigger alarm with flashing red LED if it detects smoke and leakage of combustible gas using MQ2 gas sensor. Also ThingSpeak analytics is a great bonus.
A home automation project that maps switching on/off of appliances with your entry/exit of a geofence (virtual perimeter for a real-world geographic area). Step into a cool room without having to wait for the air conditioning to start functioning? Watch the garage door open as you drive in.
This is my first post on home automation. As a 'Hello World' project, switching on/off a bulb is a common use case. This post is not an exception. But to spice it up, we'll use MQTT (MQ Telemetry Transport) - a machine-to-machine (M2M)/Internet of Things (IOT) connectivity protocol and an android ap
ESP8266 can act as both Station / WIFI client (STA_IF interface) and Access Point (AP_IF interface). AP_IF interface is active by default in MycroPython firmware on ESP826 . In the earlier post, we connected to the access point (AP mode) of ESP8266 and used WebREPL to remotely control switch on/off
So far, we have flashed MicroPython firmware onto an ESP8266 and setup WebREPL to run programs over WIFI on the chip. Now it's time for a hands-on excercise. We'll remotely switch on/off and control brightness of an LED using MicroPython WebREPL.
WebREPL daemon auto-start is disabled by default in MycroPython on ESP8266 for security reason. Here, we'll enable the same, connect to the REPL over WIFI using locally installed WebREPL client and run a "Hello World" program remotely on the chip.
By default, ESP8226 module comes with AT Firmware. In this post, we'll see how to flash MicroPython firmware onto an ESP8266 ESP-12E chip using esptool. Tools,Technologies and Components used in this article 1. ESPlorer IDE [https://esp8266.ru/esplorer/#download] 2. MicroPython [https://micropyth
To uninstall OpenCV (Open Source Computer Vision) from Raspberry Pi (Raspbian Jessie), follow the steps mentioned below in this article.
Raspberry Pi is a low cost, credit-card sized and fastest selling personal computer. In this article, we'll install and configure Oracle Java ME Embedded on a Raspberry Pi. > What is a Raspberry Pi? The Raspberry Pi is a low cost, credit-card sized computer that plugs into a computer monitor or TV,
Apache Hadoop Development Tools (HDT) [https://hdt.incubator.apache.org/] is still in development phase. So, no official distribution of Hadoop 2.2.0 Eclipse Plugin is available now. But we can build the same using winghc/hadoop2x-eclipse-plugin [https://github.com/winghc/hadoop2x-eclipse-plugin].
If you are getting "Exception from container-launch:org.apache.hadoop.util.Shell$ExitCodeException" in FAILED application's Diagnostics (or Command prompt) and "java.lang.NoClassDefFoundError: org/apache/hadoop/service/CompositeService" in 'stderr' containerlogs while running any Hadoop example on
In this post, we'll use HDFS command 'bin\hdfs dfs' with different options like mkdir, copyFromLocal, cat, ls and finally run the wordcount MapReduce job provided in %HADOOP_HOME%\share\hadoop\mapreduce\hadoop-mapreduce-examples-2.2.0.jar. On successful execution of the job in the Single Node (ps
Following exception occurs in Windows for IBM JDK 6 while executing a JUnit testcase which uses JMockit framework, in-spite of enabling the Attach API " -Dcom.ibm.tools.attach.enable=yes" - java.lang.RuntimeException: com.sun.tools.attach.AttachNotSupportedException: Unable to enqueue operation: th
In the previous post on Build, Install, Configure and Run Apache Hadoop 2.2.0 in Microsoft Windows OS [/build-install-configure-run-apache-hadoop-2-2-0-microsoft-windows-os], many people have encountered Maven build failure issue ("[ERROR] class file for org.mortbay.component.AbstractLifeCycle not f
By default, HTTPS / SSL is not configured and enabled in Tomcat Web server. SSL setup is required to make your web application accessible over HTTPS protocol. This post will guide you to configure SSL in Tomcat 7 Web server. Tools and Technologies used in this article : 1. Tomcat 7.0.47 [https://t
Many websites use URL redirection technique to forward the original request from one location to another several times for different reasons (Domain forwarding, URL shortening, Privacy protection, Maintaining similar domain names referring single website, etc.). In this post, I'll try to demonstrate
If we directly take the binary distribution of Apache Hadoop 2.2.0 release and try to run it on Microsoft Windows, then we'll encounter ERROR util.Shell: Failed to locate the winutils binary in the hadoop binary path.In the previous post - Build, Install, Configure and Run Apache Hadoop 2.2.0 in Mic
Good news for Hadoop developers who want to use Microsoft Windows OS for their development activities. Finally Apache Hadoop 2.2.0 release officially supports for running Hadoop on Microsoft Windows as well. But the bin distribution of Apache Hadoop 2.2.0 release does not contain some windows nativ
Nowadays we use different URL shortening services (like bit.ly [https://bit.ly/] , TinyURL [https://tinyurl.com/], Google URL Shortener [https://goo.gl/] etc.) to shorten long URL to fit in micro-blogging sites (like Twitter [https://twitter.com/]), to beautify a link, view analytics on link clicks,
HTTP basic authentication (BA) is a simple authentication mechanism. When a web client requests any secured web resources, server sends an HTTP response with status code 401 (Unauthorized) and WWW-Authenticate HTTP header like WWW-Authenticate: Basic realm="realm here". And browser pops up a login
In previous posts Spring Security 3 Hello World Example [/spring-security-3-hello-world-example] and Spring Security Logout Example [/spring-security-logout-example], we have used default login form generated by Spring Security framework. Now we'll set up a custom login form for authentication with
Eclipse platform provides different useful Ant tasks [https://help.eclipse.org/indigo/index.jsp?topic=/org.eclipse.platform.doc.isv/guide/ant_eclipse_tasks.htm] to interact with the workspace. If you have added any such Ant task (say eclipse.refreshLocal) in your ant build script and started getti
reCAPTCHA is a free CAPTCHA service to protect a site against spam and other types of automated abuse by bots or computer programs. reCAPTCHA provides widget which can easily be integrated to your blog, forum, comment, registration form, contact form, etc and you can be rest assured that only human
Spring Security provides Logout Handling Service for logging out by navigating to a particular URL (by default /j_spring_security_logout). LogoutFilter [http://static.springsource.org/spring-security/site/docs/3.1.x/apidocs/org/springframework/security/web/authentication/logout/LogoutFilter.html] s
This tutorial will help you to write your first Hello World Spring program. We will use Maven tool to generate the project and Eclipse IDE to implement a method which will print 'Hello World!' in the console.
Security is of great concern in any web application. If you are looking for a proven and industry standard solution to secure your Java/J2ee based application, then widely used and highly customizable authentication and access control framework - Spring Security is well worth considering. This post
Hadoop Eclipse plug-in (installed in Eclipse IDE or Spring Tool Suite) eases the experience of Map/Reduce on Hadoop. Hadoop distribution does not include Hadoop Eclipse plug-in jar, but includes source code of that plug-in. In this post, we'll see all the steps to build Hadoop eclipse plug-in from s
If you have migrated / upgraded your project to Spring Framework 3.2 and project builds successfully but when application starts, you are getting IncompatibleClassChangeError, then this post will help you to resolve the same.
Sonar is an open source platform for code quality management. It covers different aspects of code quality management like code duplication, complexity, coverage by unit tests, architecture & design, rule based defect identification etc.
This post describes how to make an HTML table (having THEAD and TBODY) sortable in few minutes using tablesorter jQuery plugin. This plugin can parse and sort many types of data like number, text, currency, URI, IP address, date, time including linked data in a table cell.
Are you planning to buy a Google's Chromebook? Want to experience how it looks like before you decide? Then this is the post worth looking into. Here we'll see how to setup, run and explore Chromium OS in Oracle VM VirtualBox.
Spring Mobile is an extension to Spring MVC for development of mobile web applications. The Spring Mobile Device module provides a feature (DeviceResolver / LiteDeviceResolver) to detect devices like mobile and tablet in the server side. Device aware view management is very useful specially when it
In this post, we'll see how to get started with a Spring Web model-view-controller (MVC) framework based Hello World web application in few steps.
Android application package file (APK) is program binary used to distribute and install Android application onto the Android operating system. Here we'll see step by step procedure of creating .apk file ready to be installed in Android device.
This tutorial will help you to write your first Android 'Hello World!' program. Here, we'll use Eclipse IDE with Android Developer Tools (ADT) plugin to build the application and Android Emulator - Android Virtual Device (AVD) to run the application which will draw 'Hello World!' text on the screen.
Logback is an increasingly popular logging framework intended as a successor to the popular log4j project. It is designed by the founder of log4j. Logback offers many advantages over log4j like faster, smaller memory footprint, automatic reloading of configuration files, automatic compression of arc
Here we'll see two examples - Copy operation & Traversing a file tree. If you have already worked using JDk 6 or earlier versions then you can see how easy it is to use JDK 7's nio package. And you need to write less code to implement the same. This tutorial shows two examples on the file IO mechan
Spring AOP uses either JDK dynamic proxies or CGLIB to create the proxy for a given target object. If the target object to be proxied, does not implement any interfaces then a CGLIB proxy will be created. In this situation if CGLIB is not present in the classpath following exception will be thrown
It is always better to get notified as soon as any major issues / exceptions occurred in the Application, instead of manually going thorugh huge logs to find probable exception messages. Apache log4j provides out of the box log Appender (called SMTPAppender) to send email alerts for the log level co
AppFog Cloud Platform is built by using the Cloud Foundry OSS bits alongside its own set of custom extensions and enhancements. AppFog provides good command line tool to deploy application but we can configure Cloud Foundry Integration plugin of Eclipse / Spring Tool Suite (STS) to deploy web applic
Simple Logging Facade for Java (SLF4J) is an abstraction of different logging frameworks (eg. log4j, java.util.logging, commons logging etc.). This tutorial describes how to configure SLF4J with log4j as underlying logging framework. To use SLF4J, it is required to include 3 jars SLF4J API (slf4j-a
This example shows how to generate random alpha numeric text which is not easy to guess.
This example shows how we can dynamically create an image from a text ('Hello World!') by writing a simple Java Servlet. In the next post, we'll see how this dynamic creation of image can be used to implement custom CAPTCHA validation.
If we save a DOM Document to an XML file using javax.xml.transform.Transformer, DOCTYPE declaration gets emitted by default. This example shows how we can retain PUBLIC and SYSTEM id of the DOCTYPE declaration for external DTD.
Jetty provides Gzip Filter to enable dynamic compression of contents like html, javascript, css etc. Just a servlet filter 'org.eclipse.jetty.servlets.GzipFilter' needs to be configured in web.xml to save bandwidth and speed up your website.
This tutorial describes how an application, deployed in IBM WebSphere Application Server (WAS) can be started or stopped programmatically using Java code.
Apache Ant is an XML-based build tool to automate different tasks like compile, assemble, test source code, building deployment packages and run Java applications. This Hello World example shows how to invoke and run a simple Ant script programmatically using java code.
Hibernate Search is a full text search engine built using Apache Lucene framework. Hibernate Search indexes your domain model, keep the index upto date and also performs full text search functionality to fetch matching domain objects. This Hello World example shows how you can setup hibernate search
This tutorial will help you to write an annotation based hibernate java program which will save some records into a database and fetch them all using Hibernate API. We will use Maven tool to build the project, Eclipse IDE to code and SQLite database to save / retrieve records. SQLite is a self-conta
This example shows how we can traverse a folder or directory structure using recursive algorithm by writing a small java program using Java File API.
Simple Logging Facade for Java (SLF4J) is an abstraction of different logging frameworks (eg. log4j, java.util.logging, commons logging etc.). This gives the developer an opportunity to plug-in desired logging framework at deployment time without changing the code. To use SLF4J, it is required to i
This simple tutorial explains you, how you can run your first Servlet class that will print "Hello World!" string in the browser. We will use Eclipse IDE to develop the code and Tomcat webserver to run the servlet code.
This example shows how an element of a java.util.ArrayList can be searched using 'binarySearch' method of java.util.Collections class. This method internally applies binary search algorithm to search a particular element.
This simple tutorial describes how you can print "Hello World!" string in your browser by writing a simple JSP (Java server pages) program developed using eclipse IDE.
This article describes how to create a "Hello World" java program using Eclipse IDE. This program will print "Hello World" in the console.