Notes 1

Java branch of what?
JavaSE, JAVA Standard Edition, Fundamentals
JavaME, JAVA mobile version of the handset
JavaEE, Java enterprise applications

Java features: cross-platform, object-oriented, multi-threaded, portable.

But the use of Java where: WEB end mobile devices such as Android end, large-scale enterprise applications, desktop applet.

Shortcuts DOS
Win + r run cmd

1. java development environment to build
   1) Download the JDK
   2) installation
   installation directory structure
   Bin: Run the tool applications
   Include: c c some header files,
   Jre: operating environment
   Lib: library .jar
   src.zip: Source file

3) to configure environment variables
to select Advanced System Settings in the right inside my computer, select the newly added two environment variables JAVA_HOME system variable in the bottom of the inside, CLASSPATH. Modified PATH
1) JAVA_HOME: jdk installation directory
2) CLASSPATH:. Compiled; the JAVA_HOME%% \ lib
. 3) the Path: may be dos;% JAVA_HOME% \ bin

2. Write the first java program, and compile and run

1. New text document, TXT files need to show extension.

2. Programming

3. The document was changed HelloWorld.java

4. Win+Rcmd

5. Compile java program: javac HelloWorld.java
   extra .class file of the file to the java virtual machine -> jvm (JRE) look at
   cross-platform, so long as the JVM .class files can be recognized, run

6. .Class file to run java HelloWorld
   three kinds of comments in Java
   annotations that can be recognized developer, jvm do not care
   1) single-line comments //
   2) Multi-line comments / * Description /
   3) documentation comment / * Description * /

Escape character, character represents a special meaning, is "\"
\ t the Tab
\ the n-newline
\ "output"
\ output \