----Download jdk (Java Dev Kit)
Official Download: http://www.oracle.com/technetwork/java/javase/downloads/index.html
Next steps: https://docs.oracle.com/javase/8/docs/
View after security
the different and meaning of the JDK and JRE: http://www.pc6.com/infoview/Article_53547.html
1. Jvm-java virtual machine! The JVM is the Java virtual machine that we often call the most central part of the entire Java implementation cross-platform, All Java programs are first compiled into a. class file that executes on the virtual machine, which means that class does not directly correspond to the machine's operating system, but instead interacts with the operating system indirectly by the virtual machine, which interprets the program to the local system for execution.
2. Jre-java Runtime environment! The JRE refers to the Java Runtime Environment and is intended for users of Java programs, not developers. Like a PC, the WIN32 application requires the operating system to run it, and the Java program we write is also required for the JRE to run. The JVM is not yet complete. class file execution, the JVM needs to call to interpret the required class library lib when interpreting. Class. In the JDK installation directory you can find the JRE directory, there are two folders Bin and Lib, you can think that the bin is the JVM, LIB is the class library that the JVM needs to work on, and the JVM and class library are called JRE together. So after the Java program is compiled into a class file, you can package the class file with the JRE and send it to a friend so that your friends can run your program (the JRE has java.exe that runs. Class).
3. Jdk-java Development kit! The JDK is an SDK for developers (the SDK is software Development Kit generally refers to a software development kit, which can include libraries, compilers, and so on), which provides a Java development environment and a running environment. There are six folders in the  JDK directory: SRC class Library Source code compression package and several other declaration files, in which the actual Java operation is the following four folders: Bin (most notably compiler Javac.exe), include (header file for Java and JVM interaction) , Lib (class library), JRE (Java Runtime Environment). Now we can see a relationship where the JDK contains the JRE, and the JRE contains the JVM (note: The bin in the JDK folder, the Lib folder and the bin in the JRE folder, Lib is different, the JDK is used for Java program development, The JRE is a function that can only run class and not compile.
JDK installation first directly unzip the JDK to C drive, then the configuration environment (right-click on "Computer", "Properties", "Advanced system Settings", "Environment variables", the environment variable in the top of the "XXX User variables" configuration environment "XXX refers to the name you give your computer", click "Create "Start configuration, my JDK installed on G disk Please install your own installed path reference self-configuration thank you! ）；
Configuration environment variables, advanced system settings, advanced systems, computers--desktop--computer--User variables for environment variable->adminstrator (specific to their user name), new or edited variables (append if already exists) To be new when not in existence;
Variable name: TEMP variable Value:%userprofile%\appdata\local\temp (please copy directly)
variable Name: TMP variable Value:%userprofile%\appdata\local\temp (please copy directly) Variable name: Java_home variable Value: C:\Program files\java\jdk1.8.0_25 (do not add ";" in the back) ）
Variable name: CLASSPATH variable value:.; %java_home%\bin;
Variable name: PATH variable Value: .; %java_home%\bin; D:\Android\eclipse-jee-juno-R-win32\android-sdk-windows\tools (the environment variables of the SDK are written in advance)
Variable name: java_home
Variable Value: C:\Java\jdk1.7.0_17
Variable name: ANDROID_SDK
Variable Value: C:\Java
Variable name: Path
Variable value:.; %java_home%\bin; C:\Java\adt-bundle-windows-x86\sdk\tools; C:\Java\adt-bundle-windows-x86\sdk\platform-tools
Variable name: CLASSPATH
Variable value:.; %java_home%\lib\tools.jar;%java_home%\lib\dt.jar;%java_home%\lib; (Note the previous. Number)
---test environment variables
Run cmd, enter "Java-version" and "javac" test command respectively to see success or not;
-----------------Download Adt-bundle for Windows
Adt-bundle is an integrated IDE, officially provided by Google Android, which already contains the Eclipse,android SDK and platform tools required by Android, and novice only needs Adt-bundle Can quickly build an Android development environment. official:https://developer.android.com/sdk/index.html#download
-----------------Installing Adt-bundle
unzip the downloaded Adt-bundle-windows-xxx-xxx.zip directly to the location you need to install.
Unzip the Adt-bundle-<os_platform>.zip (the file name may be slightly different because of the version), there are three parts:1.Eclipse2.Android SDK3.SDK Manager
Run SDK manager.exe,sdk Manager to download other Android development-related components (Eclipse can also be run from Windows > Android SDK Manager if the ADT plugin is installed). Select the API to download the Android version.
---------------Install the Android SDK
Open the extracted folder inside the SDK Manager.exe (You can also run Eclipse/eclipse.exe and then open via Windows--Android SDK Manager)
Tick the Android version of the target phone you want to develop, preferably all on the hook, and then click Install package to prompt next,accept allow to wait for installation (this is a slow process)
Fifth step: Configure the Android AVD (virtual simulator)
Open Eclipse(Eclipse/eclipse.exe), (running the startup eclipse may look a little different, you can display some of the usual windows, toolbars through Windows), and then from windows- >android Virtual Device Manger opens the AVD manager.
Click on the New button to create your newly created AVD, such as, I made a simple explanation, the parameters you can actually fill in the free, click OK on the line.
You configure this AVD to be the default debug actuator for your Android app, and of course you can configure multiple.
------------------Create a Hello World project
Via File--new-> Android Application project, then enter Hello World (project name), Next,finish.
run Eclipse, create a new Android application Project, go through the default, and you'll see that two files are automatically generated: one is the interface logic Java class and the other is the XML file that the interface describes. Java class:
interface Design XML file: You can modify the changes in this interface.
-------------------from running Hello World
Simply click on Run Debug (shortcut key F11) to run it in your configured emulator.
before running, you need to set up under Android AVD (Android virtual device), ie: Android virtualization devices.
There is no AVD defined here and a new one is required.
define the brand of the virtual device, the version of Android, and the associated hardware configuration.
Quickly build Android development environment Adt-bundle and Hello World
