What is a JavaBean exactly?

Question

I understood, I think, that a \"Bean\" is a Java class with properties and getters/setters. As much as I understand, it is the equivalent of a C struct. Is that true?

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Answer 1

A Java Bean is any java class that satisfies the following three criteria:

1. It should implement serializable interface (A Marker interface).
2. The constructor should be public and have no arguments (What other people call a "no-arg constructor").
3. It should have getter and setters.

Good to note the serialVersionUID field is important for maintaining object state. Below code qualifies as a bean:

public class DataDog implements java.io.Serializable {

private static final long serialVersionUID = -3774654564564563L;

private int id;
private String nameOfDog;

//The constructor should NOT have arguments
public DataDog () {}


/** 4. getter/setter */

// getter(s)
public int getId() {
    return id;
}
public String getNameOfDog() {
    return nameOfDog;
}
// setter(s)
public void setId(int id) {
    this.id = id;
}
public void setNameOfDog(String nameOfDog) {
    this.nameOfDog = nameOfDog;
}}