Java language properties and methods. Creation of applications for Windows. C # programming language

I am 22 years old, I have an economic education. A year ago (in February - March) I did not have any programming skills, and only encountered Java in games on old Siemens (in the form of a “powered by Java” welcome window when starting the game).

A year ago I worked in the department technical support... The work is not to say that it is bad or not like it, but it is not particularly interesting. And it so happened that at one point I thought - it would be nice to have a job that you would not go to with the feeling of “damn it, work again”, but that it would bring pleasure. I thought - what would I do if I had, conditionally, a year during which I would not have to earn money, but I could do whatever I want? The answer somehow came by itself - I would sit at home and learn to program.

But mastering a programming language is a step towards success for many people who are whistling with internet ambitions. It has become synonymous with programming for World wide web... The crunch of broadcasts Pressing the ether How to see through walls Vidar implant Vision believe "Instant action" is magnetic More than skin deep Safe storage No hiding place for anyone Agility is considered a lingua franca for the Internet Big role for small satellites? The news of these tech bangs is being carefully read by the financial crowd as well as by the programmers.

Then I decided that it was up to me. I understood that it would be difficult to learn programming from scratch, that this is a temporary rollback in my career (I had no doubt that Junior Developer received less than I did in that workplace), but I took it as a step back in order to take two steps forward. ...

OK. No sooner said than done. Since I did not understand programming languages absolutely, the first idea was to learn the language that I heard most of all about (it was used to develop software in the company where I worked) - PHP. Well, the girl talked it out. She suggested that in their company (developing mobile applications), androids write in Java + their salary seems to be good. I googled, googled, thought and decided to learn Java.

For, behind the headlines, a great linguistic upheaval is taking place. At first glance, the changes may seem icy. But deep in the secret world of programming semantics, differences of opinion are accelerating. Their eruption will change the landscape of the Internet, and more, for the better.

Lots of modern languages programming has a general evolutionary background. With each new generation, programming languages tend to become more abstract and distant from the computer with which they communicate. The first generation languages spoke to the computer in ones and zeros of "machine code", which was interpreted directly by it central processing unit as instructions for manipulating the data stored in its memory. Second-generation languages, or "assembly", were developed to make it easier to write and read such instructions using a code of letters and numbers, which was later translated into 1s and 0s that the machine could understand.

My first step was traditional attempts to learn something new - arm yourself with books, master the theory, and go! This is how I got the book by Horstmann and Cornell - Java. The basics. It was March 2014.

Generally speaking, all my life I have been desperately bad at studying from books. This is probably due to the prevailing way of perception in a person. I always really learned the material only after I had practically worked it out, consolidated it, played with it. So my first attempts at learning Java from a book were doomed to failure. Although the book is good.

Unlike the languages of the first and second generations, the syntax of the third generation languages, in principle, does not depend on the computer on which they work. A separate program called a compiler is used to translate the code into machine language. These languages also offer the programmer a much more natural form of expression, but at the cost of greatly narrowing the range of problems that the language can solve.

When it came to developing the fifth generation of computer languages, this orderly evolution went awry. In fact, the Internet has made the programmer a priority, not the language. For ease of use, the elegance of computer languages so dear to academic gurus software was sacrificed. This is important for people who are building web applications on tight deadlines. Consequently, the rise of fast and dirty scripting languages over the past decade is the "sticky tape" of the World Wide Web.

Somewhere in April, I came across the CodeGym group on VKontakte.
Then everything started as if on rails. Solving problems, many problems that are accompanied by a small amount of theory is clearly the optimal way to study the material (according to at least, for me). I was sitting at home, I was sitting at work and deciding, deciding, deciding) It was then that I additionally made sure that programming is interesting to me. I couldn't remember hovering over something like that.

These languages have become widespread because they are so flexible and adaptable to the needs of the Internet. In many ways, scripting languages perceive the ideas of fourth-generation languages as a step forward in the direction of simplicity. These are known as "interpreted" languages. In other words, the computer interprets the programmer's wishes one instruction at a time, instead of first “compiling” or translating the entire program before it can run. Writing interpreted programs is a bit like getting rid of rhymed verses. comparison, writing compiled programs is more like composing a sonnet.

It took three months for me to reach level 20. It seemed to me that the further study of the language would go much faster if you had already got a job as a programmer - then you would be in this environment for 8 hours a day, 5 days a week and would develop extremely quickly.

So, in August, I started mailing out my resume. From a couple of places they sent me test tasks, according to the results of which I did not receive any job offers - looking back, I am not surprised even once - the problem I posed, perhaps, I solved, but what a bad style of coding I had) This, by the way, is a small minus of CodeGym - as long as the problem is solved and the tests are passed, the task is counted, although your code may leave much to be desired. It is enough to install the same Checkstyle plugin in Intellij IDEA, and the situation will be different - it will emphasize the "doubtful" points in the code, which will allow you to write not only working, but also beautiful, correct code.

This makes scripting languages ideal for quick fixes rather than giant projects. First of all, scripting languages are designed to act as intermediaries for other programs, rather than as units in themselves. This glue-like feature makes them so attractive for web applications where communication between programs is vital. Another trend that predated the web, but was strongly stimulated by it, is the move towards "object-oriented" programming.

The objects in question are usually convenient representations in the computer code of counterparties in the real world. The cost of paying for objects is that the language must be equipped with a large library of different classes of objects, which makes the language more cumbersome and more cumbersome to use. However, the consensus is that the benefits of storing an object library far outweigh the costs, especially these days, with processing power and memory becoming so plentiful and cheap.

Be that as it may, in September I was called for the first interview. The vacancy contained something like the following - a developer of any level, we will offer a salary corresponding to the skills.
At this interview, the tasks were approximately as follows - a code snippet was given. Is it written correctly, and what problems could there be?
I don’t remember how many of them I decided correctly. In general, it was necessary to remember about Null, almost all the questions were about it - that you should not access a method parameter without first checking it for (if param! = Null).

In exceptional cases, when the size of the problem, libraries can be minimized. Another advantage of object-oriented programming is that user groups can create and share new classes of objects. This makes object-oriented programming especially suitable for the group-like nature of the network.

Unsurprisingly, now almost every programming language that was not object-oriented is now. Meanwhile, the philosophy behind object-oriented programming itself is shifting to more high levels abstraction. A relatively new and trendy extension of this concept is the so-called "software pattern", which reflects the basic structure of successfully solving an ever-present problem in software development. Templates refer to objects as precast bricks and mortars.

As a result, I was offered to work for the first month for free (as an internship), then a salary, which is lower (although not much) than at the place of work where I was.

I well understood that I shouldn't expect great proposals, because I knew little theory, practice only in CodeGym, zero experience, and so on. Therefore, I agreed that I would leave in 2 weeks (the right time for dismissal in the old place).

While scripting and object-oriented programming represent significant new trends, the biggest shift in the past decade has been in the definition of what a programming language really is. Most important to the success of these languages is that they are embedded in an Internet-facing environment. For example, just-in-time compilers ensure that an applet, once translated into machine code, can later bypass byte code... Of course, winning the loyalty of young programmers requires more than just smart software.

In parallel with this, I submitted my resume to another company. This company offered the following:
- 2 months of Java EE training (2 times a week for 4 hours)
- if you show good results (you defend your project successfully, which you have been writing for these two months), then you are offered employment.

The company is very good, foreign, well-known, and the working conditions are excellent - in a word, I wanted to go there much more than to the place where they had already made me an offer.
The selection for training from her involved 3 stages:
1. Performing practical tasks at home.
2. If successful, you are invited to computer testing in the office.
3. In case of successful testing, on the same day you will be interviewed.

Conceptually, the two languages represent vastly different bets on the future of the Internet. Mr. Hejlsberg, not alone to speak his mind, stresses that the Internet is about data transmission, not data processing. First, it cannot perform mathematical or logical data manipulation.

A programmer issues instructions to a computer in much the same way a foreman on a construction site yells at his workers. However, there is a higher degree of abstraction - for example, architects spend time designing a building rather than issuing orders. It is a "big picture" modeling language and has been embraced by many programmers, although it is not limited to programming.

I coped with the practical tasks without any problems - here many thanks to CodeGym and their tasks, after which these tasks seemed quite simple. There were 3 tasks: on RegExp (Google helped, because I myself could not stand them and did not remember them), on algorithms (quite simple, to be more smart) and on writing / reading from a file (there are a lot of such in the CodeGym course). I was invited for computer testing.

Until now, these tools have not been translated directly into full work program... Expect to see a whole alphabet soup of new languages in the next decade. Patients who measure success in terms of lines of written code are unlikely to sympathize with this new way of developing software.

On the horizon, programming languages face a huge challenge in helping make the Internet a smarter place. A year ago, Tim Berners-Lee, the inventor of the World Wide Web, published a manifesto for the Semantic Web. His vision is that computers should be able to recognize the meaning of information on the Internet by their context and provide users with much more relevant information than web browsers currently do.

I prepared for testing using the quizful website (http://www.quizful.net/job-role/junior-java-developer). These tests helped a lot, some questions even overlapped in the end. I did the test successfully, they began to interview me.

I will probably never forget this interview in my life.

All that the person interviewing me wanted to hear from me is the basics of Java theory, such as:
- how checked exceptions differ from unchecked;
- what methods the Object class has and why they are needed;
- what are the collections and why they are;
- and a little about multithreading.

There are many ways this could happen. Of course, some semantic data may lie in the data itself. Therein lies the possibility for languages specifically designed for artificial intelligence. Such languages have been around for decades. As with Darwin's theory, determining which fits best depends on the environment, which is constantly changing. How quickly can all this happen? Expect a whole alphabet soup of new languages over the next decade.

Programming courses in Lithuania started mushrooming after rain. This is not strange - at present, programmers are most in short supply, and banks, various Western capital companies in Lithuania are only increasing the hunting grounds for gifted programmers.

CodeGym is a great course, it teaches you how to solve problems and program, but theory (for interviews) needs to be learned separately, which I was convinced of, swimming in these questions like a fish in an aquarium.

In a week, I thoroughly studied this tutorial and went for a re-interview the day before when I was expected at a new job. Apparently, the person who interviewed me was hooked most of all by my sense of purpose (I knew that if I enrolled in this internship, the further depends only on me - in two months I would have figured out everything I needed). Be that as it may, I entered this internship and refused to go to work in the place where I was offered earlier.

The courses will not let you down, but they expect that it will be naive to buy a lot of money to pay off. Some aspiring programmers avoid employers because they have to invest a lot of time and effort. Jankauskienė assured that this is resolved by the labor exchange by drawing up an individual action plan. Can be accepted after graduating from mathematics or other exact sciences and have systematic knowledge.

Fresh programmers are not interested in everything

Ivanauskas stressed that each company has defined a different definition for a novice programmer. We are a novice programmer with up to two years of experience. We are hiring them and we have a lot now. According to her, a junior programmer may work after completing a five-month programming course, but this specialist may lack knowledge.

In 2 months we were introduced to many topics from Java EE, such as: Servlets, JSP, Hibernate JSF, Spring and much, much more - as a result of the internship, we were familiar (had a rough idea) about the main stack of Java EE technologies. Also, during the internship, we wrote our own project, which at the exit had to be successfully submitted for employment.

According to Rimkute, the desire for the program is usually expressed by people who are not satisfied with the job or do not get it at all. In addition, there are a number of those who are applying for a programming course for the best place offered by an employer or those who are dreaming of their own business. However, the most important thing is a person's readiness and attitude to the learning process.

A beginner can meet half a thousand euros

The result depends on the person. A minimum of five months is required. At the end of the course, a professional exam awaits you - one who holds on and holds on and doesn't even try to try it. He seems to be an adult, but his mother checks in and makes sure that an adult child visits. Mousavi, participant of programmer courses. He argued that a beginner programmer can expect a monthly salary of around € 500, but others can also receive a higher salary because it all depends on how the person introduces the employer and what their motivation is.

I just remember my first feelings when I was at the first lecture. I looked at the task of this project (it was issued immediately at the very first lecture) and did not even closely understand where to start here and how to do it.

I also remember what it cost me to successfully make it. During these two months, almost all the thoughts in my head were that successful employment and the fulfillment of dreams were in my hands and nothing more. It didn't depend on anyone else whether I could do it. Only from me. I had already quit my job, I was sitting with almost no money, and it was really hard. I sat in the morning, sat in the afternoon, sat in the evening, but did not get tired of rejoicing - I don’t remember when I devoted myself to something with such obsession. This time once again helped me realize how much I enjoy programming and how much I would like to work in this area.

In addition, he suggested that it be noted that in order to become a good developer, specific features of a certain way, such as focusing attention and focusing on one job, are critical, regardless of whether the person has acquired knowledge in the field of programming at the university or other educational institution does not matter.

At the graduation, I presented my project. I defended it really well, apparently much better than expected, and as an exception I was not hired for my initial position, but immediately for the position of Middle Java Developer. It was December 9, 2014. I couldn't believe it, but the job offer was in front of me on my monitor. Software engineer. This happened.

On December 15, I went to work. I have never had the thought “damn it, I don’t want to go to work”. Every day, leaving home in the morning, I know why I go to work, what I will do, and how much I want it. This is insanely happy. It is worth it and it was worth the price that had to be paid to achieve your dream.

I wish all of you who really want to be a programmer go ahead in achieving your goal. She is more than real, she is very close, but you have to pay for her. To pay with your wasted time, nerves, because learning something from scratch is really not the easiest step. CodeGym helped me take these first steps with ease, and I didn’t turn my back on programming early on because of the seeming complexity and abundance of theory. Thus, I was able to bring my rather crazy idea of a radical change in the field of professional activity (even in the absence of technical education) to the end.

And you will definitely be able to.

This section covers the fundamentals of an object-oriented language. Java programming... Java is not only the language itself, but also the platform for creating and executing applications based on this language. The language was originally called Oak ("oak") and was developed by James Gosling for programming consumer electronic devices. It was subsequently renamed Java and was used to write client applications and server software.

This language is named after the Java coffee brand, loved by some programmers, which is why the official logo of the language depicts a cup of steaming coffee.

With regard to pronunciation in Russian, as in a number of others, two different norms have been formed - borrowed English ("dʒɑːvə" - "java") and traditional national "java", corresponding to the traditional pronunciation of the name of the island of Java. Sun maintains an English-speaking pronunciation throughout the world. Sometimes the slang word “Toad” is also used in everyday life (for example, the image of a toad is on the calendars of the Java Users Group).

Object Oriented Programming Language Java

The Java programming language was developed by Sun Microsystems and is object-oriented. Source Java applications converted by the compiler javac into special bytecode for execution under the control of the Java Virtual Machine.

The Java Virtual Machine (JVM) is a program that processes bytecode and passes instructions to hardware as an interpreter. One of the main advantages this method the execution of programs is complete independence from operating system and hardware, which allows Java applications to run on any device for which there is a corresponding virtual machine.

Another important feature of Java technology is a flexible security system, within which the execution of a program is completely controlled by a virtual machine. Any actions that violate the permissions assigned to the program (for example, an attempt to unauthorized access to data or to connect to another computer), cause an immediate interruption of the program.

The disadvantages of the concept of using a virtual machine include a decrease in performance, which is fought in various ways:

application of the technology of translation of byte-code into machine code directly during program operation - JIT-technology;
wide use of platform-oriented code (native code) in standard libraries, for example SWT;
hardware that provides accelerated bytecode processing, such as Jazelle technology, supported by some ARM processors.

Java versions

Java 1.0

Java development started in 1990. In 1996, the first official version- Java 1.0.

Java 1.2

The updated JDK 1.2 specification was developed in 1998 and came out under the name Java 2. The language has not changed much, but the platform received a number of additions:

Swing library for development user interface;
a set of collections;
support for Policy files and user digital certificates;
the Accessibility library;
Java 2D;
support drag-and-drop technologies;
full Unicode support, including Japanese, Chinese and Korean;
support for playing audio files of several formats;
JIT compiler.

Java 5.0

In 2004, the Java 5.0 specification came out. Since the development of this version, the official indexing has been changed; instead of Java 1.5, it would be more correct to call Java 5.0. Sun's internal indexing remains unchanged - 1.x.

Minor changes are included without changing the indexing. The word “Update” is used for this, for example Java Development Kit 5.0 Update 25. Updates are expected to include both bug fixes and small additions to the JVM API.

In version Java 5.0 a number of fundamental additions were made:

enumerated types enum;
annotations - the ability to add metadata to the program text that does not affect the execution of the code, but can be used to obtain various information about the code and its execution;
methods with an undefined number of parameters;
import of static fields and methods is allowed;
in the collection you can use Iterator objects ( foreach);
usage javadoc comments for automatic preparation of documentation;
generic programming tools generics.

Java 6

In December 2006, another release was released Java 6... Along with this release, changes have been made to the official indexing - instead of Java 6.0, the version is listed as Java 6. Minor changes, as in previous version are included in regular version updates such as Java Standard Edition Development Kit 6 Update 25.

In version Java 6 the following major changes "noticed" by the developers have been made:

Swing improved performance of OpenGL and DirectX;
added GifWriter for working with.gif files;
classes-streams for reading and transferring compressed data became available, with the ability to transfer them over the network;
archiving - the restrictions on the number of files in the archive have been removed (previously 64 Kb), the length of the file name has been increased (previously 256 characters)
the restrictions on the quantity at the same time have been lifted open files(previously it was 2000).
organized a cache management system and added support for the "no-cache" parameter in an HTTP request;
along with the already existing Gregorian and Buddhist calendars, support for the Japanese imperial calendar has been added;
you can use Java HTTP Server to create a full-fledged HTTP server with the minimum required functional properties;
the speed of calculations and the speed of I / O operations have been increased.

Java 7

Release release version Java 7 took place in July 2011. Unfortunately in the final version Java Standard Edition 7 a number of previously planned changes were not included, which it was decided to add to Java Standard Edition 8.

V new version named Java Standard Edition 7, in addition to bug fixes, several innovations were introduced:

a new, somewhat faster type verifier, called the typechecking verifier, has been added;
in collections (datasets) added interfaces for queuing;
modification of the class loader (class-loader);
URLClassLoader - release the resources held by the classloader using the close () method;
JDBC updated to release 4.1, Rowset to version 1.1;
added new next generation look-and-feel;
nio.2 - new interfaces for accessing the file system, scalable asynchronous IO interaction, full-fledged work with zip / jar archives as with file system;
support for Unicode version 6.0;
generic - change the type inference when creating an object;
Locale - the locales of the user and the graphical interface are separated; the formatting of the text and the display of the message on the screen are "locale" independent.

Java 8

Release release version Java 8 took place in March 2014. List of innovations:

Full support for lambda expressions.
Keyword default in interfaces to support default functionality.
Method references.
Functional interfaces (predicates, providers, etc.).
Streams for working with collections.
New API for working with dates.

Java technologies

There are several main families of Java technologies:

Technology	Description
Java SE - Java Standard Edition	Core Java technology including compilers, APIs, Java Runtime Environment; used to create custom desktop applications.
Java EE - Java Enterprise Edition	Enterprise-level software development technology. Used for developing WEB applications.
Java ME - Java Micro Edition	A technology for creating programs for devices with limited computing power, such as mobile phones.
JavaFX	Technology for creating graphical interfaces for corporate applications and business.
Java Card	Technology for creating programs for applications running on smart cards and other devices with a very limited volume.

Android Development Tools, Java for Android

Java actively used to create mobile applications for the operating environment Android... In this case, programs are compiled into a non-standard bytecode, for their use in virtual machine Dalvik. For such compilation, an additional tool developed by Google is used - Software Development Kit (SDK).

You can also develop applications in Android Studio, NetBeans or Eclipse using a plugin Android Development Tools (ADT) or in IntelliJ IDEA. The JDK version must be at least 5.0.