JavaBeans are reusable software components for Java that can contain data, methods, and events. They follow a set of conventions or rules that make them easily reusable in different environments. JavaBeans are often used in graphical user interface (GUI) programming and are used to encapsulate data and functionality related to a particular task or functionality.

1. They are serializable, which means they can be stored and transferred as bytes.

2. They have a zero-argument constructor, which makes them easy to create and use.

3. They expose their functionality through a set of properties or methods, which can be accessed and manipulated by other Java components.

JavaBeans can be used in a wide range of applications, including web applications, desktop applications, and mobile applications. They are often used in frameworks such as JavaServer Faces (JSF) and Spring.

In summary, JavaBeans provide a standardized way to create reusable software components in Java that can be easily integrated into different applications and environments.