Java Cross-platform principle

• Summarize 1:java Running Process

1. 1. The Java program runs in two steps: Compiling and Interpreting execution
   2. Compile Java source program into Java bytecode file (. Class) via "compiler" (bytecode file in a structurally neutral intermediate file format)
   3. Java bytecode files are interpreted as corresponding machine languages and executed using different "virtual machines"

　　　　　　

• Summarize the differences between 2:java cross-platform and C-platform

1. 1. Java: Compile once, run everywhere, C: Compile multiple times, run everywhere

   2. In the Internet situation, the platform is different, Java cross-platform more advantages

   3. Can Java span all platforms: to see if a virtual machine is available and installed

   4. Java runs fast without C language

   5. Java needs to interpret the class file as machine code and execute it, C executes the machine code

• Summary 3: Byte-code files bytecode

1. 1. . class file Binaries

   2. Format-neutral, platform-independent binary files

   3. is the product of the compilation, is the raw material of explanation

• Summary 4:java virtual machine JVM

1. 1. JVM is the abbreviation for Java Virtual machine (Java VM)

   2. The JVM is a specification for computing devices, a fictional computer that is implemented by simulating various computer functions on a real computer.

   3. The JVM is a virtual computer that executes bytecodes bytecode.

   4. Java Virtual machine is the core technology of Java, and also the foundation of cross-platform.

   5. The Java language uses a Java Virtual machine to mask information related to a specific platform, allowing the Java language compiler to generate only the target code (bytecode) that runs on a Java virtual machine, which can be run unmodified on multiple platforms.

   6. When a Java virtual machine executes a bytecode, it interprets the bytecode as a machine instruction execution on a specific platform. That's why Java can be "compiled once, run everywhere."

• Summarize the differences between 5:JDK, JRE, and JVM

Jdk:
Java Development Kit
Products for Java Developers
Jre:
Java Runtime Environment
Is the set of environments necessary to run a Java program
Jvm
Java Virtual Machine
Explain running Java bytecode files, cross-platform core

Contact: JDK contains jre,jre containing JVM.

　　　　　　　　　　

Java Cross-platform principle