201521123059 the first week of Java Program Design Study summary

First week Study summary

1. Study Summary this week

The beginning of the week we started the Java study, just started a little confused, even familiar with the software to explore for a long time, finally in the teacher gave some tutorials and textbooks installed in the case of JDK and Eclipse software, and conducted an experimental lesson programming. In class, the teacher explained to us the usage of Java related software and the writing of Java Simple experiment, we also know how to use these related software, such as Eclipse, notepad++, JDK, DVM and other software. And know that the JDK refers to the Java Development Kit, the JVM is a Java virtual machine, the Java Virtual machine is to support the operating system independent, in any system can run, just generate the target code of the bytecode file can be; Teachers also let us Open the blog and PTA and the Code cloud, Let us experience the convenience of paperless operations, but these software is not so familiar with the need to add more operations, Java related programs are not very written, after class need to learn more.

2. Written work

1. Why can Java programs run across platforms? What are the steps to execute a Java program? (please write in your own language)

Because Java virtual machines are platform-Independent, Java code is compiled to run directly on the virtual machine, which enables cross-platform operation.

Specific steps: First write the required source program, and then generate the bytecode file through the JVM, and finally through the JRE into the computer to run local code run.

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

The JDK is the Java Program Development Kit. The difference between JDK, JRE, JDK, and JVM is that the JRE is the Java Runtime Environment, which includes the JVM and Java core class libraries and supporting files, the JVM is a Java virtual machine, the JVM has its own perfect hardware architecture, has the corresponding instruction system, its main work is to interpret bytecode, And he has nothing to do with the operating system. The three software division is clear, using the JDK to write a program and call the JDK Javac compiled into bytecode, and then run the Java bytecode on the JRE, the JVM interprets these bytecode.

3, ' java HelloWorld command, HelloWorld This parameter refers to what?

Class name

4. What is the purpose of setting the path variable?

The Windows operating system uses the specified path when looking for an executable file, or the system will fail.

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?

Java is a file that ends in. Java and then translates to an executable file that ends in a. class.

C Language Program Mr. Cheng is the file that ends in. cpp and then translates to file execution at the end of the. exe

6. What kinds of development platforms are there in the Java language?

Eclipse, MyEclipse, notepad++

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

Oracle JDK Source code can only be used for personal research use, and OPENJDK7 allows its source programs to be used commercially and personally.

# #3.1 History of this week's commit

# #3.2 Experimental Summary

(1) When programming easy to play the wrong mother, and then you do not see will look for a long time.

(2) This introductory experiment can lead us to a better understanding of Java programming software.

201521123059 Java Programming the first week of learning summary