Java is a programming language that derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of computer architecture. Neesa Technologies takes fame for its expertise in Java development, our Java consulting and software development outsourcing services provide full support at every stage of projects from architecture to implementation. We provide you entire software development process in Java design and development services that can develop proficiently the services accessible from Java application servers and the J2EE framework, including Struts, Servlets and Java Server Pages (JSPs), Enterprise JavaBeans (EJBs), Java’s Messaging Services and JDBC.
What are the differences between the different Java platforms J2ME, J2SE, and J2EE? J2SE is Sun's platform that includes the Java Virtual Machine (JVM) and packages. There is the core package which is basically the contents of rt.jar in the distribution package of J2SE. Then there are specification such as Swing and Networking (if I'm correct about this latter one ).
There's also optional packages like "J2SE Optional Packages" including JAI, JCE, JDO and J3D.
There's many implementations of the J2SE platform such as Sun's JSDK, IBM's J9, Blackdown, and Kaffe. I'm sure there are more out there... Anyway, J2SE is something you'd want to build on, something you'd probably want to learn and get to know since it's the basics.
J2EE on the other hand builds on top of J2SE so to speak; J2EE needs J2SE. It includes tools to create frameworks, API specifications suitable for companies. By specification, JSP and Servlets (and Beans) are J2EE. EJB (javax.ejb, javax.enterprise.deploy.*) is J2EE. As is JMS (javax.jms), JavaMail (javax.mail), ...
Then there's J2ME (Micro Edition) which runs on portable, mobile, handheld devices. I'm honestly not that familiar with this one; I don't really have a testing environment.
J2SE is where one should start and slowly learn the core packages, later branching into the optional packages. While Servlet/JSP is J2EE, it doesn't mean it must be packaged in J2EE. It's just specified as J2EE.
One reason why J2EE is not suitable for shared hosting is because of size. Java is huge and requires a couple of GB of memory even for J2SE. Sun's J2SE package is now less than 35 MB, while the J2EE is 98 MB.
J2EE Web Application
J2EE is the technology which any computer programmer can learn without spending money from his pocket. If you ask why, the answer is simple - everything is free in the j2ee world. This site showcases more on J2EE materials, tutorial downloads, examples, interview questions, tips and tricks etc. to propel your J2EE know-how swiftly . J2EE (Java 2 Enterprise Edition) is a specification for developing enterprise and distributed applications from JavaSoft (Sun Microsystems). J2EE is not one thing; it encompasses a large set of technologies ranging from JSP to CORBA.In expectancy of the last release of the J2EE 1.0 specification and reference implementation at the end of 1999, a smaller minority of forward thinking companies began to focus on offering a complete suite of J2EE products, from web server to EJB application server.”
What is J2ME- Java2,Micro Edition
Java Platform, Micro Edition or “Java ME” (also referred to as Java 2 Platform, Micro Edition or J2ME), is a collection of Java APIs for the development of software for resource-constrained devices such as PDAs, cell phones and other consumer appliances. Java ME is formally a specification, although the term is frequently used to also refer to the runtime implementations of the specification. Java ME was developed under the Java Community Process as JSR 68. The evolution of the platform has abandoned the umbrella Java Specification Request in favor of separate JSRs for the different flavors of Java ME.
Java ME was designed by Sun Microsystems and is a replacement for a similar technology, PersonalJava. Note that Sun only provides a reference implementation and that most work targeting a non-Intel-based small device will require a vendor-supplied JVM to be available on the device.
Java ME has become a popular option for creating games for cell phones, as they can be emulated on a PC during the development stage and easily uploaded to the phone. This contrasts with the difficulty of developing, testing, and loading games for other special gaming platforms such as those made by Nintendo, Sony, and others, as expensive system-specific hardware and kits are required.
Sun Microsystems has tended not to provide free binary implementations of its Java ME runtime environment for mobile devices, rather relying on third parties to provide their own, in stark contrast to the numerous binary implementations it provides for the full Java platform standard on server and workstation machines. One of the notable omissions is for Microsoft Windows Mobile (Pocket PC) based devices, despite an open letter campaign to Sun to release a rumoured complete project “Captain America” which is such an implementation.
As of December 22, 2006, Sun Microsystems has released the J2ME source code, or significant portions of it. This is licensed under the Free and Open Source license, the GPL, and is released under the project name phoneME. See the phoneME (project page) for more information.Configurations and Profiles.
Java ME devices implement a profile. The most common of these are the Mobile Information Device Profile aimed at mobile devices, such as cell phones, and the Personal Profile aimed at consumer products and embedded devices like Set-top boxes and PDAs.
A profile is a superset of a configuration, of which there are currently two: Connected Limited Device Configuration and Connected Device Configuration.
Connected Limited Device Configuration
The CLDC contains a strict subset of the Java class libraries, and is the minimal needed for a Java virtual machine to operate. CLDC is basically used to classify myriad devices into a fixed configuration.
Mobile Information Device Profile
Designed for cell phones, MIDP boasts an LCD-oriented GUI API, and MIDP 2.0 includes a basic 2D gaming API. Applications written for this profile are called MIDlets. Almost all new cell phones come with a MIDP implementation, and it is now the de facto standard for downloadable cell phone games. However, many cellphones can run only those MIDlets that have been approved by the carrier, especially in North America..
Information Module Profile
The Information Module Profile (IMP) is a Java ME profile for embedded, “headless” devices such as vending machines, industrial embedded applications, security systems, and similar devices with either simple or no display and with some limited network connectivity.
Originally introduced by Siemens Mobile and Nokia as JSR-195, IMP 1.0 is a strict subset of MIDP 1.0 except that it doesn’t include user interface APIs in other words, it doesn’t include support for the Java package javax.microedition.lcdui. JSR-228, also known as IMP-NG, is IMP’s next generation that is based on MIDP 2.0, leveraging MIDP 2.0’s new security and networking types and APIs, and other APIs such as PushRegistry and platformRequest(), but again it doesn’t include UI APIs, nor the game API.
IMP applications are called IMlets, but in reality they are MIDlets. They subclass MIDlet, and follow the same packaging, deployment, security and life-cycle as MIDlets.
Connected Device Configuration
CDC is a subset of Java SE, containing almost all the libraries that are not GUI related. It is richer than CLDC.
A headless version of Java SE.
Personal Basis Profile
Extends the Foundation Profile to include lightweight GUI support in the form of an AWT subset.
This extension of Personal Basis Profile includes a more comprehensive AWT subset and adds applet support.