Is there a good way to forcefully stop a Java thread?

by

There is no good way to stop a thread instantly.

  • There is Thread.stop(), but it is dangerous and deprecated. Don’t use it, unless:

    1. you fully understand the problems that make it dangerous,

    2. you have thoroughly analyzed your code and determined that the problems do not apply and / or the risks are acceptable, and

    3. you don’t care that your application may end up stuck at a some version of Java if / when the method is removed1.

  • There was Thread.stop(Throwable) but it was equally dangerous2, deprecated and was removed3 in Java 11.

  • There is Thread.interrupt(), but there is no guarantee that the thread will stop quickly, or even stop at all. The behavior will depend on whether the application thread code has been designed to notice and correctly respond to interrupts. (See below.)

  • There is the approach of writing the thread to periodically check a flag; see this answer. (See below.)

The “check a flag” and interrupt() approaches are largely the same. In both cases, the thread that expects to be interrupted needs to regularly check; e.g. by calling interrupted() or isInterrupted() or by checking a flag.

The difference between the approaches is that that the interrupt() mechanism will work when the code is waiting for a notify(), join(), etcetera, or blocked in an I/O operation. Because of this, and because interrupt is an accepted application independent way of doing this, it is usually preferable to implementing an application specific flag mechanism.

1 – In the Java 18 prerelease javadocs, Thread.stop() is now shown as “flagged for removal”.
2 – Possibly more so. If you did a Thread.stop(new IOException()) for example, some code further up the call stack could easily catch the exception and subvert your “stop”.
3 – You can still use the old “stop with an exception” functionality by calling the private Thread.stop0(Throwable) method reflectively; see https://stackoverflow.com/a/67077495/139985. It would be better to avoid having to do that.

More Related Contents:

  1. How to stop a java thread gracefully?
  2. Handling exceptions from Java ExecutorService tasks
  3. Swing animation running extremely slow
  4. java.lang.OutOfMemoryError: Java heap space
  5. How to synchronize a static variable among threads running different instances of a class in Java?
  6. Are static variables shared between threads?
  7. Why should wait() always be called inside a loop
  8. Java double checked locking
  9. Is it safe to get values from a java.util.HashMap from multiple threads (no modification)?
  10. Distinguishing between Java threads and OS threads?
  11. Throttling javafx gui updates
  12. Javafx: Difference between javafx.concurent and Platform.runLater?
  13. How are Threads allocated to handle Servlet request?
  14. How can the wait() and notify() methods be called on Objects that are not threads?
  15. Java volatile modifier and synchronized blocks
  16. How to make another thread sleep in Java
  17. Setting priority to Java’s threads
  18. How do I properly do a background thread when using Spring Data and Hibernate?
  19. Java – creating a new thread
  20. Java Multithreading concept and join() method
  21. Concept behind putting wait(),notify() methods in Object class [duplicate]
  22. Is it possible to force an existing Java application to use no more than x cores?
  23. Handling Exceptions for ThreadPoolExecutor
  24. Java Synchronization [closed]
  25. Static method behavior in multi-threaded environment in java
  26. How does Keep-alive work with ThreadPoolExecutor?
  27. Removing all queued tasks of an ThreadPoolExecutor
  28. Dynamically refresh JTextArea as processing occurs?
  29. What makes the execution order of threads unpredictable?
  30. Updating your UI and forcibly waiting before continuing JavaFX

Leave a Comment