Difference b/w Java Class and Bean class

hi,
can anybody please tell me the clear difference between ordinary java class and java Bean class. i know that bean is also a java class but i donno the exact difference between the both.
can anybody please do help me in understanding the concept behind the bean class.
Thank u in advance.
Regards,
Fazlina

While researching this question, I came across this answer by Kim Fowler. I think it explains it better than any other answer I have seen in the forum.
Many thanks Kim
Hi
Luckily in the java world the definition of components is a little
less severe than when using COM (I also have, and still occasionaly
do, worked in the COM world)
Firstly there are two definitions that need to be clarified and
separated: JavaBean and EnterpriseJavaBean (EJB)
EJB are the high end, enterprise level, support for distributed
component architectures. They are roughly equivalent to the use of MTS
components in the COM/ COM+ world. They can only run within an EJB
server and provide support, via the server, for functionality such as
object pooling, scalability, security, transactions etc. In order to
hook into this ability EJB have sets of interfaces that they are
required to support
JavaBeans are standard Java Classes that follow a set of rules:
a) Hava a public, no argument constructor
b) follow a naming patterns such that all accessor and modifier
functions begin with set/ get or is, e.g.
public void setAge( int x)
public int getAge()
The system can then use a mechanism known as 'reflection/
introspection' to determine the properties of a JavaBean, literally
interacting with the class file to find its method and constructor
signatures, in the example above the JavaBean would end with a single
property named 'age' and of type 'int' The system simply drops the
'set' 'get' or 'is' prefix, switches the first letter to lower case
and deduces the property type via the method definition.
Event support is handled in a similar manner, the system looks for
methods similar to
addFredListener(...)
addXXXListener
means the JavaBean supports Fred and XXX events, this information is
particularly useful for Visual builder tools
In addition there is the abiliity to define a "BeanInfo' class that
explicitly defines the above information giving the capability to hide
methods, change names etc. this can also be used in the case where you
cannot, for one reason or another, use the naming patterns.
Finally the JavaBean can optionally - though usually does - support
the Serializable interface to allow persistence of state.
As well as standard application programming, JavaBeans are regularly
used in the interaction between Servlets and JSP giving the java
developer the ability to ceate ojbect using standard java whilst the
JSP developer can potentially use JSP markup tags to interact in a
more property based mechanism. EJB are heaviliy used in Enterprise
application to allow the robust distribution of process
HTH.
Kim

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Moderator message: what is the difference between your question and a question that we'd welcome here in the forums?
[Rules of engagement|http://wiki.sdn.sap.com/wiki/display/HOME/RulesofEngagement]
Edited by: Thomas Zloch on Nov 22, 2010 1:17 PM

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Difference b/w Java Class and Bean class

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