A Java package is a technique for organizing Java classes into namespaces similar to the modules of Modula, providing modular programming in Java. Java packages can be stored in compressed files called JAR files, allowing classes to be downloaded faster as groups rather than individually. Programmers also typically use packages to organize classes belonging to the same category or providing similar functionality. A package provides a unique namespace for the types it contains. Classes in the same package can access each other's package-private and protected members.
In general, a package can contain the following kinds of types. A package allows a developer to group classes (and interfaces) together. These classes will all be related in some way – they might all have to do with a specific application or perform a specific set of tasks. The Java API is a collection of packages – for example, the javax.xml package. The javax.xml package and its subpackages contain classes to handle XML.
Android (from its former owner Android, Inc.) is a mobile operating system (OS) currently developed by Google, based on the Linux kernel and designed primarily for touchscreen mobile devices such as smartphones and tablets. Android's user interface is mainly based on direct manipulation, using touch gestures that loosely correspond to real-world actions, such as swiping, tapping and pinching, to manipulate on-screen objects, along with a virtual keyboard for text input. In addition to touchscreen devices, Google has further developed Android TV for televisions, Android Auto for cars, and Android Wear for wrist watches, each with a specialized user interface. Variants of Android are also used on notebooks, game consoles, digital cameras, and other electronics.
Since 2013, Android is the best selling on tablets; and on smartphones the OS is dominant, thereby giving it the largest installed base of all operating systems of any kind.
Initially developed by Android, Inc., which Google bought in 2005, Android was unveiled in 2007, along with the founding of the Open Handset Alliance – a consortium of hardware, software, and telecommunication companies devoted to advancing open standards for mobile devices.As of July 2013, the Google Play store has had over one million Android applications ("apps") published, and over 50 billion applications downloaded. An April–May 2013 survey of mobile application developers found that 71% of developers create applications for Android, and a 2015 survey found that 40% of full-time professional developers see Android as their priority target platform, which is comparable to Apple's iOS on 37% with both platforms far above others. At Google I/O 2014, the company revealed that there were over one billion active monthly Android users, up from 538 million in June 2013.
Android Jelly Bean is the name given to three major point releases of the Android mobile operating system developed by Google, spanning versions between 4.1 and 4.3.1.
The first of these three, 4.1, was unveiled at Google's I/O developer conference in June 2012, focusing on performance improvements designed to give the operating system a smoother and more responsive feel, improvements to the notification system allowing for "expandable" notifications with action buttons, and other internal changes. Two more releases were made under the Jelly Bean name in October 2012 and July 2013 respectively, including 4.2—which included further optimizations, multi-user support for tablets, lock screen widgets, quick settings, and screen savers, and 4.3—contained further improvements and updates to the underlying Android platform.
Android 4.1 "Jelly Bean" was first unveiled at the Google I/O developer conference on June 27, 2012, with a focus on "delightful" improvements to the platform's user interface, along with improvements to Google's search experience on the platform (such as Knowledge Graph integration, and the new digital assistant Google Now), the unveiling of the Asus-produced Nexus 7 tablet, and the unveiling of the Nexus Q media player.