What is GET and POST method in HTTP and HTTPS Protocol? Answer

GET and POST method in HTTP and HTTPS are two most popular methods used to transfer data from client to server using  HTTP (Hyper Text Transfer Protocol)  protocol. Both GET and POST can be used to send requests and receive response but there are significant differences between them. The difference between GET and POST in HTTP or HTTPS is also a popular interview question in JSP and any web programming interview. Since HTML is independent of any web server technology like Java, ASP or PHP and HTTP is core protocol in space of the internet, the importance of a clear understanding of GET and POST method can not be ignored.

How to Fix javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException in Java? Example

If you are working in a Java web or enterprise application that connects to any other web server using HTTPS you might have seen the "javax.net.ssl.SSLHandshakeException". This is one of the particular cases of that error. If you know how SSL and HTTPS work that when a Java client connects to a Java server the SSL handshake happens. In these steps server return certificates to confirm its identity, which the client validates against the root certificate he has in its truststore. If Server returns a certificate that cannot be validated against the certificates a browser or Java client holds in its truststore then it throws the "sun.security.validator.ValidatorException: PKIX path building failed:
sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target".

10 Examples of Vim or VI editor in UNIX and Linux

Vim or VI editor tutorial in UNIX 
VI Editor is like notepad in UNIX but it’s extremely powerful and has a sophisticated feature to work as complete IDE. No matter which version of UNIX you are working or which flavor you are using you always find either VI editors or VIM there. VI is a very large topic and I am not covering every aspect of it what I am sharing here is some examples of using VI editor in UNIX or Linux. most of the time we use only 10% of VI editor and never know 90% of it, to be frank, I also don't know many of VI features by heart but I always search for it, see people working in VI and learn from their experience as well.

5 JSTL Core IF Tag Examples in JSP - Tutorial

<c:if>  or if the tag of JSTL core tag library in JSP is one of the most versatile and useful tags. JSTL if tag allows you  to test for a condition, like checking for a particular parameter in requestScope, sessionScope, or pageScope. You can also check any parameter in request parameters and headers or can check for a variable in JSP page using <c:if> tag. JSTL if tag helps a lot to reduce the amount of Java code from JSP  page and if used, along with expression language JSTL core tag library, can remove almost all Java code from JSP files. Earlier we have seen examples of JSTL foreach tag and JSTL core set tag and this JSP JSTL tutorial is based on if the tag of the JSTL core tag library.

Difference between URL-rewriting URL-encoding in Servlet JSP? Answer

URL-rewriting vs URL-encoding in Servlet JSP

The main difference between URL-rewriting and URL-encoding is that URL-rewriting is a technique to maintain user session if cookies are not enabled on the client browser or browser doesn't support cookie while URL-encoding is a way to pass a string to the server containing special characters by converting special characters like space into some other characters like +. People often confuse between URL encoding and URL rewriting because of there names which sound quite similar for new guys but functionality wise they are totally different to each other, Also servlet encodeURL() method adds more confusion because its sounds like its used for URL Encoding but indeed used for URL Rewriting.

Tibco RV Tips and Commands with Examples

This is the third post on series of "Tibco tutorials" , In this article, I am posting some of the most useful commands which I used while working in tibco rv in many application , they are extremely useful and must be in developers top of head who is working in tibco rv.  Before writing these "tibco tutorial" series I looked for some introductory simple TIBCO tutorial which explains concept of tibco rv in simple word and give us working knowledge of TIBCO but I did not found any. TIBCO is most heavily used middleware solution on enterprise world and form backbone of many large enterprise including global banks.

How to deal with Common FIX Session Connection Issues? Solutions

FIX Protocol Session Connectivity
Hi guys, in this post I would like to share my experience with financial information exchange (FIX) Connections which is essential to set up FIX connectivity for trading purposes. Financial information exchange (FIX) Connections are used in both Client Connectivity and Exchange connectivity space (in case exchange supports financial information exchange (FIX) Protocol or you are connecting to any broker via FIX  Protocol).

InOrder traversal of Binary tree in Java using Recursion and Iteration - Example Tutorial

This is the second article about tree traversal algorithms using Java. In the first part, we have seen the pre-order algorithm for visiting all nodes of the binary tree and today we'll learn about the InOrder traversal. As I told you before, unlike array and linked list, the binary tree has several ways of traversal. The traversal algorithms are broadly divided into depth-first and breadth-first traversal algorithms depending upon how the algorithm actually works. As the name suggests, depth-first explores binary tree towards depth before visiting sibling, while breath first visits all nodes in the same level before going to next level, hence it is also known as level order traversal. 

How to Print all Leaf Nodes of Binary tree in Java - Recursion and Stack Examples

Binary tree based questions is very common in Java or any other programming job interviews. One of the frequently asked binary tree questions is "write a program to print all leaf nodes of a binary tree". In order to solve this problem, you must know what is a leaf node? A leaf node in a binary tree is a node whose left and right child is null. They are actually the last nodes of any binary tree. In a typical programming interview, you would be given a binary tree and asked to write a program to print all leaf nodes. Usually, all binary tree related questions can be solved easily using recursion because a tree is a recursive data structure, but you should also know how to solve them without recursion.

Top 10 Maven Plugins Every Java Developer Should Know

In the last couple of years, Maven has become the de-facto build tool for Java applications. Though there are challenges that exist from tools like Gradle, I think the dominance of Maven will help it to win the final battle. When I started with Maven, I was happy with just dependency management but then I come to know about maven plugins which let you customize your build-up to the level you can do with ANT. These plugins provide true power to Maven to automate most of the build-related tasks like compilation, testing, packaging, deployment, and even committing the source code into the remote source repository.

ThreadLocal Memory Leak in Java web application - Tomcat

ThreadLocal variables are infamous for creating memory leaks. A memory leak in Java is the amount of memory hold by an object which is not in use and should have been garbage collected, but because of unintended strong references, they still live in Java heap space. There are many ways memory leak can be caused in Java but when this memory leak is caused due to the ThreadLocal variable, it’s referred to as ThreadLocal memory leak. In our last post about the ThreadLocal variable, we have seen How the ThreadLocal variable can make SimpleDateFormat thread-safe and also raised points that in a managed environment like the J2EE application server or a web servers like Tomcat, Jetty, WebSphere or Weblogic use of ThreadLocal should be avoided.

How to get max memory, free memory and total memory in Java? Example

Getting free memory, total memory and max memory on JVM is using Runtime class in Java. and many java programmers is interested to know whether they have any relationship with JVM argument -Xms and -Xmx which is used to specify starting heap size and maximum heap size of JVM. I have touched this on 10 Points on Java heap and how to set heap size in ANT and Maven but here we will see some way to find out starting and maximum heap size from Java program.

Tibco Tutorial: Fundamentals of Tibco RV Messaging - Network, Service, and Daemon on RVD

This is in continuation of my tibco tutorial series where I will discuss tibco rv on the application developer's point of view as middleware or messaging solution.As discussed in earlier tibco tutorials, tibco is used for communicating between two systems e.g. client and server or server to server, here we will see some of the basic terms used in tibco rv  world.

Top 20 FIX Protocol Interview Questions and Answers

Its' been a while since I shared FIX protocol interview questions. So here is the new set of top 20 FIX protocol interview questions. These are the question which is mostly asked in while interviewing any developer or support professional which has some knowledge of FIX protocol. Given the number of clients, brokers and exchanges using FIX protocol it’s really a great thing to have on your resume and can land you some very well paying jobs in the street. 

How to set JAVA_HOME environment in Linux, Unix and Windows? Example

JAVA_HOME is a system environment variable that represents the JDK installation directory. When you install JDK in your machine (Windows, Linux, or UNIX) it creates a home directory and puts all its binary (bin), library(lib), and other tools. In order to compile the java program "javac" tool should be in your PATH and in order to get that in PATH we use the JAVA_HOME environment variable. Many tools like ANT and web servers like tomcat use JAVA_HOME to find java binaries. In this article, we will see how to set the JAVA_HOME environment variable in the different operating systems including Windows (Windows 7, Vista, XP) and Linux (Unix).