201521123114 Java programming 1th Week of study summary

1. Summary of this week's study

The Java language has the following features: simplicity and simplicity, platform independence, object-oriented, multi-threading, distribution, high performance, robustness, and so on.

2. Written work

1. Why are Java programs running across platforms? What are the steps to execute a Java program?

Java-owned JVMS (virtual machines) can translate programs into machine code that the system understands in different systems.

The source code is written first, then the bytecode file is generated by the JVM, and then the JRE runs the environment's code to the cost, and finally executes the file.

2. What is the difference between a JDK?JDK,JRE,JVM?

JDK Full name Java Development Kit, refers to the free Java Development Kit.

The JRE is the Java execution environment; The JVM is a virtual machine, and the main task is to interpret bytecode.

3.java HelloWorld Command, what does this parameter refer to in HelloWorld? Is it a file name? What is the meaning of this command?

HelloWorld is the class name. Is the file name that runs the HelloWorld.

What is the use of 4.path variables? What is the use of classpath variables?

Executable files can be found when running Java files; Tell the Java execution environment where to find the classes or packages needed to execute the Java program .

5. What is the difference between writing a program in Java and running a program and running it with the C language, and the intermediate and target files that are generated?

The generated file format for Java authoring is. class, and the target file is. java;

The generated file format for the C language is. cpp and the destination file is. exe.

What are the 3 app versions of the 6.Java language? What is the relationship between versions?

J2ME (Java 2 Platform, Micro Edition): Mini version of the Java platform

J2SE (Java 2 Platform, Standard Edition): Java Platform

EE (Java 2 Platform, Enterprise Edition): Enterprise version of the Java platform

What is the difference between a 7.Oracle jdk and an open JDK?

The former source code may be used for personal research purposes, but it is prohibited for commercial use, while the latter allows for commercial usage.

What are the main applications of 8.Java? What are your goals and expectations in this course?

Java is mainly used in enterprise management systems, electronic equipment, internal procedures. My goal is to be able to write some small programs.

3. Using the code cloud to manage Java code

4. Experimental summary

The first touch of Java has many similarities to the previously learned C language; Learning shortcut keys can improve the speed of writing code.

201521123114 Java programming 1th Week of study summary