What is Java?

First, let's Look at Java features

? Simple----Java designers have removed many of the complex features in C + +, such as pointer manipulation and operator overloading

? Object-oriented----Everything in Java is an object. Therefore, focus on the data, the methods of manipulating objects in the application, and the process (all objects)

? Robustness----Java checks code when compiling and interpreting

? Security----Java provides controlled environments for executing programs, as well as multi-layered security controls (pointers are not allowed)

? cross-platform----compile once, run everywhere (virtual machine)

? Garbage collection----No memory leaks (GC)

? open source, open platform

Java three operating platforms

Beginners will certainly be confused, why to provide three kinds of running platform

? J2SE (Java 2 platformstandardedition)

§java Standard Edition or Java standard platform

? EE (Java 2 Platform Enterprise Edition)

§java Enterprise Edition or Java Enterprise Platform

? J2ME (Java 2 Platform Micro Edition)

§java Mini-version or Java mini-platform

Three core mechanisms of Java

? A Java Virtual machine (JVM) is a computer that is emulated by software or hardware on a single computer.

§java compiler

? generates a class file for a Java Virtual machine and is therefore platform independent.

§java Interpreter

Responsible for running the Java Virtual machine's code on a specific platform.

? garbage collection mechanism (garbage collection)

? code security Detection

Java Cross-platform principle

What is Java?