An "if" statement is a flow control structure in most programming languages that branches execution flow depending on a binary condition, generally evaluated at runtime. If statements are also commonly also called conditionals. When using this tag please also include an appropriate language tag, such as e.g. "java" if your question is language-specific.

GENERAL UBUNTU SUPPORT IS OFF-TOPIC. Support questions may be asked at https://askubuntu.com/. Ubuntu is a free desktop and server operating system based on Debian GNU/Linux. This tag is for programming questions specific to Ubuntu.

A framework for building Java web applications based on the Model-View-Controller (MVC) pattern. It promotes flexible and decoupled code from the underlying view technologies.

Ruby on Rails is an open-source web development framework written in Ruby. Ruby on Rails follows the principle of convention over configuration, freeing you from having to re-invent things to stay productive. Use this tag only for Rails 3-specific questions, and also tag those questions [ruby-on-rails].

Use this tag for code that must compile as C++11 (not using any features introduced in C++14 or later).

Microsoft Access, also known as Microsoft Office Access, is an application development and database development tool from Microsoft. It combines the Microsoft Jet/ACE Database Engine with a graphical user interface and software-development tools. Other database engines, such as SQL Server, can also be used as a database server for Access applications.

Parsing refers to breaking an artifact into its constituent elements and capturing the relationship between those elements. This tag isn't for questions about the self hosted Parse Platform (use the [parse-platform] tag) or parse errors in a particular programming language (use the appropriate language tag instead).

Elasticsearch is a free and open, distributed, RESTful search engine based on Lucene.

Topics relating to application security and attacks against software. Please don't use this tag alone, that results in ambiguity. If your question is not about a specific programming problem, please consider instead asking it at Information Security SE: https://security.stackexchange.com

User Interface (UI) is the system through which people interact with a computer. This tag can be used for UI-related programming questions. Note that there's a separate Stack Exchange site for User Interfaces, Interactions with the Computer and User Experience design: https://ux.stackexchange.com.

Authentication is the process of providing a proof of identity or verifying identity.