How does the JVM ensure that System.identityHashCode() will never change?

by

Modern JVMs save the value in the object header. I believe the value is typically calculated only on first use in order to keep time spent in object allocation to a minimum (sometimes down to as low as a dozen cycles). The common Sun JVM can be compiled so that the identity hash code is always 1 for all objects.

Multiple objects can have the same identity hash code. That is the nature of hash codes.

More Related Contents:

  1. How to deal with “java.lang.OutOfMemoryError: Java heap space” error?
  2. Could not reserve enough space for object heap
  3. Memory address of variables in Java
  4. Java heap terminology: young, old and permanent generations?
  5. Setting JVM heap size at runtime
  6. What is the largest possible heap size with a 64-bit JVM?
  7. Java Refuses to Start – Could not reserve enough space for object heap
  8. Understanding max JVM heap size – 32bit vs 64bit
  9. Encourage the JVM to GC rather than grow the heap?
  10. Why a sawtooth shaped graph?
  11. how to increase java heap memory permanently?
  12. how to choose the jvm heap size?
  13. How to see JIT-compiled code in JVM?
  14. Running jmap getting Unable to open socket file
  15. How to fix java.lang.UnsupportedClassVersionError: Unsupported major.minor version
  16. Jvm takes a long time to resolve ip-address for localhost
  17. What is in Java object header?
  18. Is there a way to get a reference address? [duplicate]
  19. String s = new String(“xyz”). How many objects has been made after this line of code execute?
  20. Hashcode and Equals for Hashset [duplicate]
  21. Setting JVM/JRE to use Windows Proxy Automatically
  22. Would Java inline method(s) during optimization?
  23. what is the difference between == operator and equals()? (with hashcode() ???)
  24. How to view the current heap size that an application is using?
  25. How to set timezone to UTC in Apache Spark?
  26. How do I give Jenkins more heap space when it’s running as a daemon on Ubuntu?
  27. Java’s “os.name” for Windows 10?
  28. How does the JVM terminate daemon threads? or How to write daemon threads that terminate gracefully
  29. Is it possible to use sun.misc.Unsafe to call C functions without JNI?
  30. JVM_FindSignal function continuously allocates native memory

Leave a Comment