Please run the following test:

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.SimpleBeanInfo;
import javax.swing.SwingBeanInfoBase;
import javax.swing.AbstractButtonBeanInfo;

public class Test {
    public static void main(String[] args) throws IntrospectionException {

        BeanInfo i = Introspector.getBeanInfo(SimpleBeanInfo.class);
        System.out.println("test: " + i.getMethodDescriptors().length + " descriptors");
    }
}



Output:
"test: 18 descriptors"

But if replace "SimpleBeanInfo.class" with "SwingBeanInfoBase.class" or "AbstractButtonBeanInfo.class", it fails:

Exception in thread "main" java.lang.NullPointerException
at javax.swing.SwingBeanInfoBase.getAdditionalBeanInfo(SwingBeanInfoBase.java:70)
at java.beans.Introspector.<init>(Introspector.java:445)
at java.beans.Introspector.getBeanInfo(Introspector.java:204)
at testfs.Test.main(Test.java:14)
Java Result: 1


Is that what expected?

Checked with JDK9 b70, OS - Win 7.