java-bean

I am new to the java language and have this doubt. I searched several places on the internet and asked several friends JAVA p ... but none could explain to me clearly what the difference between the two. What is the difference between JavaBean and POJO?

I'm starting to read about layered java development, and I've read something about bean, an encapsulated class. But I couldn't find any content that actually explained the purpose and an example. So, what is a Bean and what is it for?

When I make parameterized constructors, I create an empty constructor as well. In the empty constructor, should I always make the call to super ()? Why? (Take into consideration, that my class is just a JavaBean.)

I have the following code snippet: <p:selectOneMenu id="agencia" converter="agenciasConverter" value="# ... t().getAttributes().get("agencia") How to use f:attribute to pass object that was selected in the select to the backbean?

Can anyone simplify what is a bean ? I have already read the description on the website of proprio Spring but it did not make ... at is happening in reality, I want to understand what need to declare this Bean is supplying. Hugs and thanks in advance. rs