201521123068 Java programming 1th Week of study summary

1. Summary of this week's study

Java is the foundation of each application platform, learning to understand Java SE to lay the foundation;

Programming with MyEclipse or eclipse;

The Java language has the features of platform independence, facing objects (encapsulation, inheritance, polymorphism) and high security.

A source program file can contain multiple classes, but only one class is modified with public;

The file name of the source program must be the same as the class name that is decorated with public.

2. Written work

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

A: Java programs can cross the platform because the Java Virtual machine can cross-platform, the JVM will translate bytecode into the corresponding hardware platform to execute code;

To execute a Java program: write Java source files, compile them into class intermediate file, and run through the interpreter.

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

A: The JDK is the Java SDK, the Java Runtime Environment (contains the inner class library and native library), and the JVM is a Java virtual machine.

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

A: HelloWorld is the file name and this command represents the Helloworld.class file.

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

A. Path is a path variable, in order for the operating system to find the specified tool program;

The CLASSPATH variable is intended to allow the Java execution environment to find the developed Java program, the. class file.

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?

A: Java: Write Java source files, compiled into class intermediate file, through the interpreter, run;

C Language: Build source code (generate. c/.cpp file), compile (generate. o file), link (generate executable. exe file).

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

A: Java SE, Java EE, Java me Three versions of the application;

Relationship: Java SE is the foundation of each application platform, Java EE is based on Java SE and Java me is the smallest of the Java platform versions.

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

A: The Oracle JDK implementation is the Sun JDK implementation, the Oracle JDK uses the JRL, and the open JDK uses the GPL, the former source code can be used for personal research use, but prohibit any commercial use, the latter allows commercial usage.

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

A: Java desktop applications, Java Web Applications, Java enterprise-class applications, Java embedded applications;

I want to listen carefully and learn to master Java programming skills.

3. Using the code cloud to manage Java code

4. Experimental summary

Code writing process is always complex, the need for patience and careful, there is perseverance to do a good thing, the road long its repair far, refueling!

201521123068 Java programming 1th Week of study summary