What is the exact meaning of static fields in Java?

by

Static doesn’t quite mean “shared by all instances” – it means “not related to a particular instance at all”. In other words, you could get at the static field in class A without ever creating any instances.

As for running two programs within the same JVM – it really depends on exactly what you mean by “running two programs”. The static field is effectively associated with the class object, which is in turn associated with a classloader. So if these two programs use separate classloader instances, you’ll have two independent static variables. If they both use the same classloader, then there’ll only be one so they’ll see each other’s changes.

As for an alternative – there are various options. One is to pass the reference to the “shared” object to the constructor of each object you create which needs it. It will then need to store that reference for later. This can be a bit of a pain and suck up a bit more memory than a static approach, but it does make for easy testability.

More Related Contents:

  1. Why is the Java main method static?
  2. Why isn’t calling a static method by way of an instance an error for the Java compiler?
  3. How to lock compiled Java classes to prevent decompilation?
  4. Java: Static vs inner class [duplicate]
  5. When does static class initialization happen?
  6. Java stack overflow error – how to increase the stack size in Eclipse?
  7. private final static attribute vs private final attribute
  8. Java – how to load different versions of the same class?
  9. What is the replacement for javax.activation package in java 9?
  10. GC overhead limit exceeded
  11. limiting java ssl debug logging
  12. Analyzing gc logs
  13. Java Error: Cannot make a static reference to the non-static method
  14. How does the JVM ensure that System.identityHashCode() will never change?
  15. Java static serialization rules?
  16. Memory effects of synchronization in Java
  17. Java static final values replaced in code when compiling?
  18. Bytecode features not available in the Java language
  19. What makes hot deployment a “hard problem”?
  20. Java verbose class loading
  21. How and where to use Static modifier in Java?
  22. Why have one JVM per application?
  23. Why doesn’t the JVM cache JIT compiled code?
  24. What are bytecodes and how does the JVM handle them
  25. Why a sawtooth shaped graph?
  26. If I compiled a Java file with the newest JDK, would an older JVM be able to run the .class files?
  27. Behavior of static blocks with inheritance
  28. How to extend a final class in Java
  29. Java for-loop optimization
  30. Difference between Dynamic and Static type assignments in Java

Leave a Comment