What is difference in between Java Class and Bean?

A JavaBean is basically a Java class which satisfies a few simple rules (it must have a public no-arg constructor, no public instance variables, properties have getters and setters; actually, you can get around the last rule by supplying a BeanInfo object for your bean). JavaBeans were originally conceived for graphical application builder tools, but that emphasis has shifted considerably and they're now used almost everywhere.

A Bean can have associated support classes: a BeanInfo class providing information about the bean, its properties and its events, and also property editors and a graphical customizer.

A Bean is a Java class, but a Java class does not have to be a bean. In other words a bean in a specific Java class and has rules that have to be followed before you have a bean.