Several versions of Java and concepts such as JRE,JDK-"reprint" JDK, Java SE, Java EE, Java me I should choose

We usually use some of the software, a part of the need for Java environment support, but sun so many products, let people dazzling version number, before looking at the same abbreviation, let us choose the time often deterred, had to follow the feeling to go. So here's what I'm going to be trying to tell you about, first of all, let's look at the many Sun products:
:http://developers.sun.com/downloads/

Haha has not expanded their sub-options, let people dazzling, the following describes the use of the more widely used nouns it:
AJ2SE
JAVA2 platform Standards (JAVA2 Platform standard Edition), mainly for personal PC desktop application development, including:
1. Java Runtime (Java Runtime Environment,JRE), including basic class libraries, Java virtual machines, applet components, etc.;
2. Java SDK (Java Development Kit,JDK), is the extension set of the JRE, including the Java compiler and debugger, and so on.
TwoJava
JAVA2 Platforms Enterprise Edition (JAVA2 Platform Enterprise Edition), primarily for complex enterprise applications, based on J2SE.
ThreeJ2ME
JAVA2 Platform Mini-version (JAVA2 Platform micro Edition), mainly for mobile devices, embedded devices, such as the development, based on J2SE.
Now let's briefly summarize the historical long stream of Java:
The 1995 Java language invention, followed by the introduction of the main JDK. Until 98, JAVA2 platform was released and divided into J2SE, Java EE, J2ME. To 04 J2SE, the Java EE, J2ME accordingly renamedJava SE、Java EE、Java ME, publish Java SE 5 with an internal version number of 1.5. Released by 06, Java SE 6, with an internal version number of 1.6. Today, Java SE has the latest version number 6, Java EE The latest version number is 5, Java me no version number.
Let's see what each of the Java SE, Java EE, and Java me includes, so it's natural to distinguish them:

In fact, the JDK and Java SE Development Kit are the same, and the JRE and Java SE Runtime environment are the same, we look at:
Java EE is based on Java SE, it also has the Java EE 5 SDK but not the JDK, because the Java EE 5 SDK is also based on JDK, let's look at:
Java EE and Java me are all based on Java.  

The more straightforward point:

JVM (Java Virtual machine Java VM)
Can be understood as a virtual computer, with the basic computing methods of the computer,
It is primarily responsible for interpreting bytecode files generated by Java programs into machine instructions on specific system platforms.
Let specific platforms such as Windows run these Java programs.

JRE (Java Runtime Environment Java Run environment)
Includes the Java Virtual machine (JVM Java) and the core class libraries required by the Java program, etc.
If you want to run a well-developed Java program, you only need to install the JRE in your computer.

JDK (Java Development Kit Java Development Kit)
The JDK is available to Java developers with Java development tools,
The JRE is also included. So with the JDK installed, you don't have to install the JRE separately.
The development tools include the build tool (Javac.exe) packaging Tool (Jar.exe), etc.

In simple terms: Java programs developed using the JDK are delivered to the JRE to run.
Three relations:
JVM: A machine instruction that converts a bytecode file into a specific system platform.
The core class library of the Jre:jvm+java language.
Development tools for Jdk:jre+java.

Several versions of Java and concepts such as JRE,JDK-"reprint" JDK, Java SE, Java EE, Java me I should choose