Hashmap concurrency issue

by

Yes, it will cause major problems. One example is what could happen when adding a value to the hash map: this can cause a rehash of the table, and if that occurs while another thread is iterating over a collision list (a hash table “bucket”), that thread could erroneously fail to find a key that exists in the map. HashMap is explicitly unsafe for concurrent use.

Use ConcurrentHashMap instead.

More Related Contents:

  1. Custom thread pool in Java 8 parallel stream
  2. Random errors when changing series using JFreeChart
  3. How to wait for all threads to finish, using ExecutorService?
  4. Is there an advantage to use a Synchronized Method instead of a Synchronized Block?
  5. Update JLabel every X seconds from ArrayList – Java
  6. When and how should I use a ThreadLocal variable?
  7. What is the difference between Thread.start() and Thread.run()?
  8. Practical uses for AtomicInteger
  9. Why use a ReentrantLock if one can use synchronized(this)?
  10. Is volatile expensive?
  11. Java swing GUI freezes
  12. Different types of thread-safe Sets in Java
  13. Parallel streams, collectors and thread safety
  14. question about “Java Concurrency in Practice” example
  15. How do I implement task prioritization using an ExecutorService in Java 5?
  16. Constructor synchronization in Java
  17. What is an “incompletely constructed object”?
  18. More efficient way for pausing loop wanted
  19. Java Concurrency: CAS vs Locking [closed]
  20. Correct way to synchronize ArrayList in java
  21. How to interrupt a BlockingQueue which is blocking on take()?
  22. Uninitialized object leaked to another thread despite no code explicitly leaking it?
  23. ThreadPoolExecutor Block When its Queue Is Full?
  24. How LongAdder performs better than AtomicLong
  25. LinkedBlockingQueue vs ConcurrentLinkedQueue
  26. How to reduce java concurrent mode failure and excessive gc
  27. Does a breakpoint halt all threads?
  28. What is optimum thread pool size for simple program running cpu based tasks in Java
  29. How to combine 3 or more CompletionStages?
  30. When is it preferable to use volatile boolean in Java rather than AtomicBoolean? [duplicate]

Leave a Comment