Most of you will agree that HashMap is a most favorite topic for discussion in interviews nowadays. Now, I am continuing this discussion with you all.
I am assuming that if you are interested in the internal working of HashMap, you already know the basics of HashMap, so I’m skipping that part. But if you are new to the concept, follow official java docs.
Single Statement Answer If anybody asks me to describe “How HashMap works?”, I simply answer: “On the principle of Hashing”. As simple as it is. Now before answering it, one must be very sure to know at least the basics of Hashing. Right?
Many times while using WordPress, if we try to use “$” to access jQuery, we get an error the “$ is not defined”. This happens because the jQuery library which is included in WordPress loads in “no conflict” mode. In the no conflict mode jQuery returns the control of “$”, and it is no longer accessible as a function, variable, or alias for jQuery. WordPress does this in order to prevent compatibility problems with other JavaScript libraries that can be loaded.
Apache™ Hadoop® is an open source software project that enables the distributed processing of large data sets across clusters of commodity servers. It is designed to scale up from a single server to thousands of machines, with a very high degree of fault tolerance. Rather than relying on high-end hardware, the resiliency of these clusters comes from the software’s ability to detect and handle failures at the application layer.
Hadoop 1 popularized MapReduce programming for batch jobs and demonstrated the potential value of large scale, distributed processing. MapReduce, as implemented in Hadoop 1, can be I/O intensive, not suitable for interactive analysis, and constrained in support for graph, machine learning and on other memory intensive algorithms. Hadoop developers rewrote major components of the file system to produce Hadoop 2. To get started with the new version, it helps to understand the major differences between Hadoop 1 and 2.
What’s HTTP? HTTP stands for Hypertext Transfer Protocol. It’s the network protocol used to deliver virtually all files and other data (collectively called resources) on the World Wide Web, whether they’re HTML files, image files, query results, or anything else. Usually, HTTP takes place through TCP/IP sockets (and this tutorial ignores other possibilities).
A browser is an HTTP client because it sends requests to an HTTP server (Web server), which then sends responses back to the client. The standard (and default) port for HTTP servers to listen on is 80, though they can use any port.
It’s quite straightforward to integrate Log4j into the Spring MVC application. First, include Log4j.jar library into your project dependency, then create a log4.properties file to define the Log4j’s appender and put this file into the project classpath, Done.
In the tutorial, we show you how to integrate the Log4j 1.x logging framework into the Spring MVC application.
Add Log4j Library to Your Project Download the Log4j library from the official website, or via Maven :
Ajax is a term coined by Jesse James Garrett and that became popular since the publication of the article Ajax: A New Approach to Web applications, published in February 2005, is a shortcut for Asynchronous JavaScript and XML.
The normal behavior of the Internet that involves sending pages to the browser is completely changed by the use of Ajax.
Ajax has become commonplace with its integration in HTML 5 and JavaScript frameworks, and in fact, the interest of developers has moved to HTML 5 for its new tags and APIs that accompany it. Among these, WebSocket appears as the successor to Ajax, because it is a superior means of communication between an application and the server or the backend.
After all the services, DAO, and support classes are tested then it’s time for the controller. Generally, this is hard to test and most developers (based on observation) would rather just test it via Selenium or worse, by hand. That can work but it makes testing logic branches difficult and not to mention it’s time-consuming. Plus no active developer would be willing to wait for browser tests to run before checking in code. Luckily the Spring MVC Test project can do full controller testing via unit tests, it was such a success that it’s now in Spring MVC core as of version 4.0.5.
In this tutorial, you will learn how to develop a Spring 4 MVC Hello world example. We hope this tutorial will give you a quick start with Spring MVC development using the latest Spring 4 Release.
Technologies used:
Spring 4.0.4.RELEASE JDK 1.8 Tomcat 7.0.53 Maven 3.2.1 Eclipse Java EE IDE ( Eclipse Kepler) Maven Project Setup In Eclipse Let us start with the creation of a Maven web project in Eclipse. A maven web project archetype will create all the necessary folder structures required for a web project. We assume that you have installed the Maven plugins for Eclipse.