Answer:- The most crucial difference between operational and programmer errors is that the operational errors are not bugs but problems with the system such as to request timeout or hardware failure. On the other hand, the programmer errors are actual bugs in the application.

Answer:- In Node.js, an EventEmitter is a class that includes all the objects capable of emitting events. This can be achieved by attaching named events that are emitted by the object using an eventEmitter.on() function. Thus whenever this object throws an event, the attached functions are invoked synchronously.

Answer:- In Node.js, there are two ways to read and execute files: readFile and CreateStream. • The readFile() process is a fully buffered process that returns the response only when the complete file is pushed into the buffer and is read. This process is called a memory-intensive process, and in the case of large files, the processing can be very slow. • On the other hand, the createReadStream() is a partially buffered process that treats the entire process as an event series. The entire file is split into chunks and then processed and sent back as a response one by one. After completing this step, they are finally removed from the buffer. Unlike the readFile process, the createReadStream process is effective for the processing of large files.

Answer:- In Node.js, the concept of Punycode is used for converting one type of string into another type. Punycode is an encoding syntax used for converting Unicode (UTF-8) string of characters into a basic ASCII string of characters. Now, the hostnames can only understand the ASCII characters so, after the Node.js version 0.6.2 onwards, it was bundled up with the default Node package.

Answer:- In Node.js, the concept of Punycode is used for converting one type of string into another type. Punycode is an encoding syntax used for converting Unicode (UTF-8) string of characters into a basic ASCII string of characters. Now, the hostnames can only understand the ASCII characters so, after the Node.js version 0.6.2 onwards, it was bundled up with the default Node package.

Answer:- In Node.js, the libuv library is used to handle the Thread pool. The libuv library is a multi-platform C library that supports asynchronous I/O-based operations such as file systems, networking, and concurrency.

Answer:- Bootstrap is a HTML, CSS, and JS framework for building the rich web applications with minimal effort. This framework emphasis more on building mobile web applications.

Answer:- There are few reason why we choose Bootstrap for building websites • Mobile Support: For mobile devices it provides full support in one single file rather than in separate file. It supports the responsive design including adjusting the CSS based on the different types of device, size of the screen etc. It reduces extra effort for developers. • Easy to learn: Writing application in bootstrap is easy if you know CSS and HTML • Browser Support: It supports all the popular browsers like Firefox, Opera, Safari, IE etc.

Answer:- The key components of Bootstrap are CSS : It comes with plenty of CSS files Scaffolding : It provides a basic structure with Grid system , link styles and background Layout Components : List of layout components JavaScript Plugins: It contains many jQuery and JavaScript plugins Customize: To get your own version of framework you can customize your components

Answer:- Class loader is a part of JRE (Java Runtime Environment) which loads Java classes into Java virtual environment. Class loaders also does the process of converting a named class into its equivalent binary form.

Answer:- In Bootstrap there are two types of Layout available • Fluid Layout: Fluid layout is used when you want to create a app that is 100% wide and use up all the width of the screen • Fixed Layout: For a standard screen you will use fixed layout (940 px) option

Answer:- For creating page layout through a series of rows and columns that house your content Bootstrap Grid Sytem is used.

Answer:- For more specialized layouts offsets are a useful feature. For more spacing they can be used by pushing column over. For example, .col-xs=* classes do not support offset but they are easily replicated using an empty cell

Answer:- Column ordering is one of the feature available in bootstrap and you can easily write columns in an order and show them in another one. With .col-md-push-* and .col-md-pull-* the order of the column can be easily changed.