Introduction to Java

There are three versions of Java:

J2SE (Java 2 Standard Edition) / Java SE
J2EE (Java 2 Enterprise Edition) / Java EE
J2ME (Java 2 Micro Edition) / Java ME

Java SE

Java SE covers fundamentals of Java programming such as:

Object Orientation
Exception Handling
Multithreading
Collection Framework
Streams

Java SE can be used to create stand-alone applications. A stand alone application is an application designed without using client-server architecture and without distributing application logic over multiple machines.

Client-Server architecture is where a client sends a request to the server, server takes the request, executes something, server then generates response to respective clients, client takes the response and display the response to the user

Diagram illustrating a stand-alone Java SE application running on a single machine.

Examples of stand-alone applications are calculator, vim, eclipse, terminal emulator and GIMP.

About 5% of applications are standalone applications. Java SE is a dependancy for lots of other technology such as Java EE, Hadoop, Selenimum, etc.

Java EE

Java EE covers server side programming.

Java EE can be used to create enterprise applications or distributed applications.

A server side or distributed application is an application designed and executed using client-server architecure or by distributing application logic over multiple machines.

Diagram illustrating a stand-alone Java EE enterprise application running on a server machine. — Diagram illustrating a Java EE application running on a server machine.

About 95% of applications a client-server applications or distributed applications.

J2ME

J2ME covers micro programming, it can be used to create mobile based applications.

A mobile based application is an application designed and executed on the basis of mobile hardware system.