Java Java - A technology invented by Sun Microsystem (RIP) and now an Oracle product. « Write once, run everywhere ». JVM – Java Virtual Machine. It abstracts your OS and executes the Java byte code.
Java JRE – Java Runtime Environment. Set of tools aims to execute a Java program The virtual machine The byte code interpreter and converter into native code The standard Java API JDK – Java Standard Development Kit. Its your toolbox. It allows to write Java source code and compiles it into byte code. Javac, the java compiler which converts source code (.java) into byte code (.class) Jar, the java archiver. It archives a set of class files into a jar file Javadoc, the documentation generator (abuse it!) Jdb, the java debugger A JRE
Java 2 SE Java Standard Edition. Contains the basics API. Its desktop computer oriented. A set of basics API Example: Collections
Java 2 EE Specifications of standard API Different implementation of same API Example: JPA is implemented by Eclipselink, OpenJPA, Hibernate Defined by the Java Community Process (JCP) Certifications Architecture pattern Large scale Multi-tiers (Presentation Logic, Business Logic, Persistence) Scalable Reliable Secure J2EE = an extension of Java SE to facilitate the development of enterprise applications ?
J2EE servers Java EE is a set of specifications implemented by different containers. Containers are Java EE runtime environment that provides certain services to the component they host… Antonio Goncalves, Beginning Java EE 6 Platform with GlassFish 3 J2EE server = Web container + J2EE implementation RuntimeWeb container J2EE4 certified J2EE5 certified J2EE6 certified TomcatYes Open EJBYes Geronimo = Tomcat + Open EJBYes JBoss ASYes IBM Websphere ASYes Yes >=WAS 8 Glassfish Open sourceYes Oracle GlassfishYes Apache TomEEYes
To sum up J2EE extends J2SE J2EE is multi-tiers/layered J2EE is a set of specifications, not a set of implementations J2EE server = container + J2EE implementations A J2EE server host J2EE applications