5 Tricks And Ideas About The Best Selenium Web Driver + JAVA Training

By Piyush Biswas

The present modern world is very sophisticated. Almost everything works on a single click of a button. With the popularity of software and digitalization gaining momentum in every sphere of today's world, Selenium has become one of the most commonly used automation tools for testing in the world. There is also a great rise in demand for selenium experts. Gradually, selenium is on the hot-seat to become the best test automation tool for testing web-based applications.

When it comes to execution of application testing without these of selenium remote control otherwise the server, the latest technology you can find is the selenium web driver. They actually ease the process of testing. The software application is available at a very cheap price which in fact is the plus point and a necessity to survive in the highly competitive market like today. The online selenium training is becoming very popular because they offer good quality skill and club with the advantage of being an online course.

Now, Let us see the five tricks and ideas about the best selenium Web Services SOA Testing Course and JAVA Training

As a part of the Selenium web driver + Java training, all the trainees are given the opportunity to work on live projects. This help in understanding the working of the tool in a much better way. Common issues and problems relating to the software tool are made familiar and the trainees are equipped with the right skill to counter such issues.

When you are undergoing this training, the work experience you gain in the live projects or real-time projects can be included in your resumes to give more value to it. When one joins the selenium web driver + java training, you often get the opportunity of getting free access to a community of experts. This is very beneficial for the clarification of your doubts and helps you share new ideas. You also get the opportunity to build a healthy communication which will help you get the timely information and updates about new jobs and career opportunities.

Important materials such as daily notes and video recordings are shared after every session. This helps the trainees to learn the subject matter on their own without the need of any third person. The institutes also facilitate chatting facilities for the sole purpose of clarifying the doubts of the trainees.

The fact that the training is an online mode, it does not have any political boundaries meaning anyone from any part of the world can learn the software tool from world's best and most popular trainers.

It is the perfect course for anyone who wants to start automation testing or get an automation testing job. The training is also helpful in upgrading your skill. The Java basic plus advanced to ease your selenium learning process is an add-on of the training course.

Know More Detail: http://www.seleniumlabs.in/

Piyush Biswas is a versatile Indian writer who loves to write in various technology and current software etc. He has written huge number of articles, magazines on selenium software testing & automation testing training. Through his articles you can get enough information about training centres in India.

ExceptionHandler Ruby on Rails Gem

By Richard Peck

ExceptionHandler is an "error pages" gem for Ruby on Rails.

Currently at version 0.7.7.0, the gem has been downloaded over 170,000 times and is widely regarded as the "best" dynamic error pages gem for the framework. It works extremely well.

The most important thing to realize about ExceptionHandler is that it's basically designed to provide a "translation" system for Rails errors, converting them into the appropriate HTTP error that a web browser can read.

You see, whilst Rails may raise exceptions from within its core, these errors are not what you see in your browser. You see the http error that the framework delivers to the web server. This http error is accompanied by an "HTTP Message Body" which is what the browser displays on the page.

In other words, when dealing with Rails errors - if you want to actually show "branded" error pages (with your own layout or another one) - you have to "hack" Rails to deliver those specific pages when errors occur. The pages that are shown have NO bearing on what the user sees in their web browser; they're simply there to provide a "branded" way for them to engage with it.

Whenever Rails raises an exception inside its application - that error (it could be anything such as a database problem or something) is only valid for the Rails application. What Rails does is "translate" that error into one of two types of HTTP error (which a browser can read): 4xx (client error) or 5xx (server error).

Every time you use a "web" application, your computer is sending a request for data on port 80 of a publicly accessible IP address. If the other computer (server) has a "web server" application running on port 80, it will accept the request and respond with HTTP based data (which will typically include HTML code).

The entire "web" is a public directory for the "Internet", meaning that if you the IP (or equivalent domain name) for a connected computer, you should be able to access it via the "HTTP" (Hyper Text Transfer Protocol). This HTTP protocol is the core of how the "web" works, and why most people get confused when dealing with "errors" in their Rails based applications.

HTTP "errors" are not really errors at all but erroneous responses. Each "error" you see is still an HTML page, displayed with a corresponding HTTP status code.

Since HTTP is a "stateless" protocol, it has to work with what's known as a "request/response" pattern - essentially meaning that every single time you send a new request to a web service, that request is treated as entirely new.

This is opposed to "stateful" processes, which "retain state" between requests; in the sense of native applications or similar. The point is that what you see with HTTP errors is a response to an erroneous request. They're really just status codes which explain that.

To do this properly, you have to be able to "translate" Rails-based errors into the appropriate HTTP error response. This is done by the ActionDispatch::ShowExceptions middleware - which calls a middleware "hook" ("exceptions_app") to determine which "HTML" response to show in the body of the erroneous message.

It uses the "rescue_responses" hash to determine which HTTP error code to match any Rails exceptions to. This hash can be extended within Rails, allowing users to map different Rails-based "exceptions" to the appropriate HTTP response code.

Say your application raises an error with ActiveRecord.

If it cannot find a particular item in the database - Rails will raise the ActiveRecord::NotFound exception class. This is not an HTTP-compatible error; it's simply a "Rails" exception. The key is that it has to be "translated" into an error that HTTP-based browsers can understand. This is where ActionDispatch::ShowExceptions comes in.

ShowExceptions essentially takes the exception object - passes it through the "rescue_responses" hash (to get an appropriate HTTP status code) and - crucially - invokes the "exceptions_app" middleware hook to generate the "HTTP message body" for the response...

wrapper = ExceptionWrapper.new(backtrace_cleaner, exception)

status = wrapper.status_code

request.set_header "action_dispatch.exception", wrapper.exception

request.set_header "action_dispatch.original_path", request.path_info

request.path_info = "/#{status}"

response = @exceptions_app.call(request.env)

The key thing to realize here is that @exceptions_app is what ExceptionHandler has been built to manage.

Every time Rails raises an exception, the HTTP protocol still remains no matter what. In other words, you're always going to require sending an HTTP status code and message body to the requesting web browser... the difference lies in what you send.

The problem for Rails is that @exceptions_app defaults to the "routes" - which means that it will load 404.HTML or 500.HTML from the /public directory of your application. Whilst this works, the pages are unprofessional and static.

To change the pages, ExceptionHandler overrides the "@exceptions_app" hook with its own controller and views. This means that you're basically able to invoke "dynamic" web pages with Rails.

The way ExceptionHandler works is to use the application's "default" layout (typically "application") for 4xx errors, and include a completely custom "exception" layout for 5xx errors. The custom layout is generally recommended as 5xx errors denote server issues, which means that if you're using a layout that references the database (as most "application" layouts do), it could cause an infinite loop to occur.

This means that if you have an error - say ActiveRecord cannot load a record from the database - Rails will still invoke ActiveDispatch::ShowExceptions.

However, due to ExceptionHandler overriding the "exceptions_app" hook, rather than the static 404.HTML / 500.HTML pages being called, the controller and views pipeline provided by the gem are invoked instead.

If you want to read more about ExceptionHandler, you're welcome to look at its Github responsitory.

Exciting New Features In Java 9

By Arun Kumar Biswal

In September, Oracle released Java SE 9 with over 150 new features. The latest version of the widely used programming language comes with several new features and APIs to accelerate development of applications for both large and small devices. At the same time, the features provided by Java 9 help programmers to improve application's performance, security, and maintainability. Hence, it becomes essential for programmers to understand some of the key features provided by Java 9.

What Programmers Need to Know about Java 9?

Module System

The developers can now use Better Support for HTML5 and JavaScript to divide JDK into multiple modules. Each modular JAR file contains a module descriptor. The developers can define interdependency of various modules through requires statements. The modularity makes it easier for programmers to run JVM modules smoothly on small devices that lack additional memory. At the same time, they can also run only the APIs and JVM modules required by the application.

Ahead-of-Time Compilation

Java 9 improves code compilation process significantly through ahead-of-time (AOT) compilation. The programmers can leverage AOT compilation compile Java classes into native code even before the virtual machine launches them. AOT compilation improves the performance of both large and small applications by overcoming major shortcomings of just-in-time (JIT) compilation. Unlike JIT compilation, AOT compilation ensures that no Java method remains uncompiled.

Real-Eval-Print-Loop Tool

Java 9 comes with a new real-eval-print-loop (REPL) command line tool - Shell. Shell is designed with features to evaluate declarative statements and expressions interactively. A programmer can use Shell to assess the quality of Java code before compilation. He can simply enter a piece of code and collect feedback. Shell even has the capability to complete tabs and add required terminal semicolons automatically. The new REPL tool makes Java compete with widely used programming languages like Python and Scala.

Better Support for HTML5 and JavaScript

The improved Javadoc documentation tool provided by Java 9 has the capability to generate HTML5 markup. Also, latest version of the programming language supports several new characters, blocks, and scripts as part of Unicode 8.0 encoding standard. At the same time, Java 9 comes with an improved and lightweight JavaScript engine that makes it easier for programmers to embed JavaScript code in Java applications. The developers can further enable ECMAScript code analysis in various IDEs and frameworks directly with the parser API for Nashorn's ECMAScript syntax tree provided by JDK.

Improved Stream API

While writing Java code, programmers use strings to express calculations. Java 8 accelerated stream processing by providing the Streams API. Java 9 comes with an improved version of the Streams API that enables developers to take and drop items from Stream based on specific conditions by adding methods. Also, the improved Streams API is designed with features to create a stream for nullable value and iterate over Stream elements.

Multi-Resolution Image API

Java 9 introduces a new interface - MultiResolutionImage - to create a single multi-resolution image by encapsulating multiple images with varying resolutions. The developers can further use the Multi-Resolution Image API provided by Java 9 to get various variants of a single image. Also, they can use the API to select a particular image based on the required resolution. Hence, the Java programmers can now use a single API to create a unified multi-resolution image and get resolution-specific image variants. http://2 client API

Java 9 completely changed the way applications make HTTP calls. It replaces the HttpURLConnection API with a new HTTP client API. The HTTP client API supports both http://2 and WebSockets. However, the API is currently not a part of Java SE. It is implemented as an incubator module which lives under the jdk.incubtor namespace. But the HTTP client API supports the latest communication standards, while overcoming the shortcomings of the HttpURLConnection API.

Stack-Walking API

While writing Java code, programmers explore ways to access and filter stack trances efficiently. The latest version of Java simplifies stack walking by providing the Stack-Walking API. The new API makes it easier for programmers to access and filter stack trace information. It further supports both short and long walks. Hence, it becomes easier for programmers to access and filter the entire stack without relying on the virtual machine to capture the stack information.

Datagram Transport Layer Security (DTLS) API

Java 9 helps developers to build secure applications by providing an API for Datagram Transport Layer Security (DTLS). The API keeps client and server communication secure by eliminating chances of data tampering, message forgery, and eavesdropping. Also, it provides communication privacy to a variety of applications that use Datagram Transport Protocol (DTP). Despite being developed based on Transport Layer Security (TLS), DTLS implements SSL protocol.

Improved Process API

Often Java programmers find it daunting to control and manage operating system processes. The Process API provided by earlier version of developers to access the native code and write additional code. But the improved Process API provided by Java 9 makes it easier for programmers to control and mange operating system processes. They can use the API to make a Java application interact with the operating system directly. Also, they can take advantage of the new methods to handle process names and states without writing additional code.

Deprecated Features

Despite providing several new features, Java 9 does not support some of the features provided by Java 8. For instance, it no longer supports Applet API. The Java web developers have to switch from Applet API to Java Web Start to launch applications from web browsers. Likewise, Java 8 speeds up development of garbage collectors in HotSpot virtual machine by deprecating Concurrent Mark Sweep (CMS) garbage collectors. While using the most recent version of Java, programmers also lack option to receive Java warnings on import statements and select JRE at launch time.

On the whole, Java 9 comes with several new features to simplify development of applications for both large and small devices. However, some of the binaries and source introduced by Java 9 are not compatible with earlier versions of the programming language. The programmers even have to make several changes to the code and upgrade libraries while migrating existing applications to Java 9. But the developers must consider upgrading their existing applications to Java 9 to take advantage of these new features and enhancements. Java developers also should use these highly recommended tools for better programming.

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