[Java] [#1 Java] Basics of Java-Prerequisites before study-

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Hello, this is Moe. This time, I would like to write about Java, which made me come into contact with programming languages.

Java in the first place

Java is one of the programming languages that needs to be compiled and used to create programs. You can use Java to develop various programs that run on various computers.
Programmers who have learned Java are currently the most demanded on the market, so if you think about the future, you may want to start studying Java for the time being.
However, Java has some unusual characteristics compared to other programming languages.

  • Java features -Easy to learn and standard grammar -Supports object-oriented support for large-scale development -A wealth of prepared and convenient instructions -Versatility that works the same in any environment, Windows, Mac, Linux

Java works everywhere! It is a language created with the motto. Therefore, instead of translating it into a machine language that can be understood by a specific computer, we create an intermediate language that can be used by any computer.
When running, the Java Virtual Machine (Java VM) installed on each computer translates it into machine language and executes it. It is easy to understand that it is necessary to first translate into English and then into other languages instead of translating from Japanese to Chinese or Japanese to German to execute the program. think.

Try to write Java source code

The Java file is completed by adding the extension “.java” in a text editor, but it cannot be executed without preparing the execution environment. I built the environment by referring to Use Adopt OpenJDK.

Java integrated development environment

After creating a file, Java translates the program called compiling the source code, converting it into byte code, and then executing it. By the way, the translation software that does this translation work is called a compiler. After compiling, it instructs the software called interpreter to execute the bytecode. This interpreter has a mechanism called JavaVM inside, and converts bytecodes into machine language that the CPU can understand.

Programs written by humans are translated and executed only in this way so that they can be understood by the computer, but there is rarely any development in which such settings are made by themselves.
Actually, “Coding”, “Compile”, “Test”, “Debug”, etc. required for Java development are performed by using the “Integrated Development Environment (IDE)” that enables efficient program development. There are several types of this, but let’s prepare a development environment that suits you. By the way, I’m using Eclipse and IntelliJ IDEA, and I’m mostly using Eclipse. In selecting the development environment, I read [For beginners] Description of Java development tools with images.


For program development, there is a convenient environment called an integrated development environment, and there is a framework that assists that development. This is a system in which the entire processing flow is implemented in advance, and you can implement and embed some of the specific processing yourself. By utilizing this framework, developers can improve development efficiency.

Is the basic story of Java like this? I’ll post again!