In the 1880s Herman Hollerith invented the concept of storing data in machine-readable form. ĭata and instructions were once stored on external punched cards, which were kept in order and arranged in program decks. The first computer program is generally dated to 1843, when mathematician Ada Lovelace published an algorithm to calculate a sequence of Bernoulli numbers, intended to be carried out by Charles Babbage's Analytical Engine. He gave the first description of cryptanalysis by frequency analysis, the earliest code-breaking algorithm. In the 9th century, the Arab mathematician Al-Kindi described a cryptographic algorithm for deciphering encrypted code, in A Manuscript on Deciphering Cryptographic Messages. In 1801, the Jacquard loom could produce entirely different weaves by changing the "program" – a series of pasteboard cards with holes punched in them.Ĭode-breaking algorithms have also existed for centuries. In 1206, the Arab engineer Al-Jazari invented a programmable drum machine where a musical mechanical automaton could be made to play different rhythms and drum patterns, via pegs and cams. As early as the 9th century, a programmable music sequencer was invented by the Persian Banu Musa brothers, who described an automated mechanical flute player in the Book of Ingenious Devices. Programmable devices have existed for centuries. See also: Computer program § History, Programmer § History, and History of programming languages Reverse engineering is a related process used by designers, analysts, and programmers to understand an existing program and re-implement its function. Software engineering combines engineering techniques with software development practices. These might be considered part of the programming process, but often the term software development is used for this larger process with the term programming, implementation, or coding reserved for the actual writing of code. Tasks accompanying and related to programming include testing, debugging, source code maintenance, implementation of build systems, and management of derived artifacts, such as the machine code of computer programs. Proficient programming thus usually requires expertise in several different subjects, including knowledge of the application domain, specialized algorithms, and formal logic. The purpose of programming is to find a sequence of instructions that will automate the performance of a task (which can be as complex as an operating system) on a computer, often for solving a given problem. The source code of a program is written in one or more languages that are intelligible to programmers, rather than machine code, which is directly executed by the central processing unit. Programming involves tasks such as analysis, generating algorithms, profiling algorithms' accuracy and resource consumption, and the implementation of algorithms (usually in a chosen programming language, commonly referred to as coding). Now that you're generally acquainted with reflection as a theoretical concept, let's proceed to its practical application! We won't learn all of the Reflection API's methods-just the ones that you'll actually encounter in practice.Computer programming is the process of performing a particular computation (or more generally, accomplishing a specific computing result), usually by designing and building an executable computer program. It's hard to imagine that Java, as a platform, could have achieved such widespread adoption without reflection. Reflection is used in almost all modern Java technologies. Get and set values of an object's fields by name.Create an instance of a class whose class name is unknown until run time.Find out what methods belong to implemented interface(s).Get information about a class's modifiers, fields, methods, constants, constructors, and superclasses.Here is a basic list of what reflection allows: You can literally juggle classes and their components. In other words, an understanding how reflection works in Java will open up a number of amazing opportunities for you. Reflection and a logically consistent model for issuing error information make it possible to create correct dynamic code. Reflection lets you work with types that weren't present at compile time, but which became available during run time. Reflection lets you explore information about fields, methods, and class constructors. Reflection ( from late Latin reflexio - to turn back) is a mechanism to explore data about a program while it is running. There is a short, accurate, and popular definition on the Internet. In Java, reflection is implemented using the Java Reflection API.
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