在MANIFEST.MF文件中将类声明为Java-Bean的目的是什么？

Question

当我打开rt.jar的MANIFEST.MF文件时，我可以找到来自swing包的类声明为Java bean。这些类和普通的Java类有什么区别？

MANIFEST.MF文件：

Manifest-Version: 1.0
Implementation-Vendor: Oracle Corporation
Implementation-Title: Java Runtime Environment
Implementation-Version: 1.8.0_191
Specification-Vendor: Oracle Corporation
Created-By: 1.7.0_07 (Oracle Corporation)
Specification-Title: Java Platform API Specification
Specification-Version: 1.8

Name: javax/swing/JCheckBoxMenuItem.class
Java-Bean: True

Name: javax/swing/JDialog.class
Java-Bean: True

Name: javax/swing/JSlider.class
Java-Bean: True

Name: javax/swing/JTextField.class
Java-Bean: True

Name: javax/swing/JTextPane.class
Java-Bean: True

Name: javax/swing/JTextArea.class
Java-Bean: True

Name: javax/swing/JList.class
Java-Bean: True

Name: javax/swing/JFormattedTextField.class
Java-Bean: True