Thread.destroy has never been implemented. If it were implemented, it would be deadlock prone in the manner of Thread.suspend. (In fact, it is roughly equivalent to Thread.suspend without the possibility of a subsequent Thread.resume.) We are not implementing it at this time, but neither are we deprecating it (forestalling its implementation in future). Although it would certainly be deadlock prone, it has been argued that there may be circumstances when a program is willing to risk a deadlock rather than to exit outright.
Getting Started
Object-Oriented Programming Concepts
Language Basics
Object Basics and Simple Data Objects
Classes and Inheritance
Interfaces and Packages
Handling Errors Using Exceptions
Threads: Doing Two or More Tasks at Once
I/O: Reading and Writing
User Interfaces That Swing
Appendix A. Common Problems and Their Solutions
Appendix B. Internet-Ready Applets
Appendix C. Collections
Appendix D. Deprecated Thread Methods
Appendix E. Reference