For HttpSessionBindingListener, the object that implements that intereface will be notified, when Session Attributes of that object is added, removed or replaced...
For HttpSessionAttributeListener, the class that implements this interface must be specified in the Deployment Descriptor. Whenever any session attributes are added, removed and replaced, it will be notified...
As conclusion, HttpSessionBindingListener deals with one session object and HttpSessionAttributeListener deals with all available session objects...
Hope it clears you...
Co-author of SCMAD Exam Guide, Author of JMADPlus
SCJP1.2, CCNA, SCWCD1.4, SCBCD1.3, SCMAD1.0, SCJA1.0, SCJP6.0