Java的版本

J2EE- Java 2 Enterprise Edition (企業版本) 更名為Java EE

J2SE- Java 2 Standard Edition (標準版本) 更名為Java SE

J2ME-Java 2 Micro Edition (微型版本) 更名為Java ME

(參考來源：http://zh.wikipedia.org/wiki/Java_EE)

JDK and JRE

JDK- Java Development Kit
 To develop Java applications and applets, you need the JDK (Java Development Kit), which includes the JRE
(source link：official website)

The JDK is a development environment for building applications, applets, and components using the Java programming language.

 The JDK includes tools useful for developing and testing programs written in the Java programming language and
running on the Java^TM platform.(source link：official website)


JDK 7 is a superset of JRE 7, and contains everything that is in JRE 7, plus tools such as the compilers and debuggers necessary for developing applets and applications(source link：official website)



JRE- Java Runtime Environment
You must have a copy of the JRE (Java Runtime Environment) on your system to run Java applications and applets
(sourse link：official website)


JRE 7 provides the libraries, the Java Virtual Machine (JVM), and other components to run applets and applications written in the Java programming language(source link：official website)

架構圖

結論：
jdk是提供給開發者使用的開發環境，jdk是jre的superset，也就是說jdk包含了jre在其中
，比jre多了一些開發上需要的工具，如compilers, debuggers

jre提供了class libraries, JVM和可以跑applets和application的其他元件