Essay on Java

Java is one of many high-level programming languages ​​that uses software abstraction (detail reduction and decomposition) to create software for computers and many other electronic devices. Compared to low-level programming languages, high-level programming languages ​​use a combination of natural language (any language used by humans) and typical computer terminology to create a more understandable and simple programming format I will create it. Figures 1 and 2 show the difference between creating a simple program called "Hello World" in an assembly (low-level programming language) and creating Java.

Like human languages, programming languages ​​have different writing difficulties; some are easier to write, others need more computer knowledge to understand. See more

The Java program has three parts that are important to the operation of the program. In all Java applications, code always starts with a class (write instruction) definition. In the class there are main ways to pass specific requirements to the program. Finally, create a specific task other than main as a function to perform the specific tasks required for the program. Three parts of Java

As mentioned earlier, Java consists of various parts, but usually three parts are the most important parts of Java. They are classes, methods, and objects. Class is a blueprint for creating objects used in programs. This method is a Java statement that must be in the class, and at least the "main ()" method is required to make the Java program work. Finally, the object stores the current state and displays the behavior when called by the method.

Java is usually written in a standalone development environment (IDE). The IDE is a program with all the resources to write a program in one place. Unlike C ++, a language like Java, programs written in Java can be used on any operating system that can run Java virtual machines. This makes Java one of the most versatile and widely used languages ​​in commercial software programs and other areas. The process of writing Java

Today, Java is widely used to create solutions, and millions of websites use Java for web applets and applications. Java is widely used on popular Web sites such as LinkedIn, Twitter, eBay etc. Google has adopted Java as the primary language for writing Android applications. Any developer who creates an application using the Google Android API will write in Java. Part of this popularity is because Java source code can be compiled into bytecode and then run on any server or client computer where Java Virtual Machine is installed. In other words, the Java program is platform-independent and can be run on various operating systems such as common IoT operating systems such as Windows, iOS, Linux, RIOT, Contiki, FreeRTOS etc.

Kotlin is running on JVM (Java Virtual Machine) as of today. In fact, it depends mainly on JVM and also functions in Java, so this can be adopted quickly. This allows Kotlin to coexist with Java in a single application development, enabling a smoother learning transformation (that is, converting Java code to Kotlin, decompiling the Kotlin code and converting it to its Java source You can display the code).

Oracle software that converts Java bytecode (intermediate language) programs into machine language and executes them. The Java Virtual Machine (JVM) is a Java platform runtime engine that makes programs written in Java or other languages ​​compiled into Java bytecode and can be run on any computer with native JVM. The JVM runs on the client and server, and the web browser can activate the JVM when it encounters a Java applet.

First let's explain how Java applications work on Windows or how Android applications work on phones. All Java code runs in the Java virtual machine, so you can easily run Java applications on any device with Java installed. This Java virtual machine (JVM) is like a sandbox. But this is not completely isolated. Problems arise when you develop games, require a game engine or multimedia codec, or when you need maximum security. This is where the JVM is not enough. This is because even if the actual Java code is executed within the Java virtual machine, in order to communicate with the underlying hardware in order to utilize the hardware-provided resources, since the kernel can communicate, the code It is because we first need to communicate with the kernel. Hardware Even so, you can not communicate directly with the kernel from the so-called "sandbox" of the Java virtual machine. It must use a bridge called Java Native Interface (JNI). This is the main problem of Java