Why is there no Constant feature in Java?

by

Every time I go from heavy C++ coding to Java, it takes me a little while to adapt to the lack of const-correctness in Java. This usage of const in C++ is much different than just declaring constant variables, if you didn’t know. Essentially, it ensures that an object is immutable when accessed through a special kind of pointer called a const-pointer When in Java, in places where I’d normally want to return a const-pointer, I instead return a reference with an interface type containing only methods that shouldn’t have side effects. Unfortunately, this isn’t enforced by the langauge.

Wikipedia offers the following information on the subject:

Interestingly, the Java language specification regards const as a reserved keyword — i.e., one that cannot be used as variable identifier — but assigns no semantics to it. It is thought that the reservation of the keyword occurred to allow for an extension of the Java language to include C++-style const methods and pointer to const type. The enhancement request ticket in the Java Community Process for implementing const correctness in Java was closed in 2005, implying that const correctness will probably never find its way into the official Java specification.

More Related Contents:

  1. Compile-time constants and variables
  2. Java’s final vs. C++’s const
  3. Cannot refer to a non-final variable inside an inner class defined in a different method
  4. Change private static final field using Java reflection
  5. Difference between final and effectively final
  6. How does the “final” keyword in Java work? (I can still modify an object.)
  7. What is the best way to implement constants in Java? [closed]
  8. Why should I use the keyword “final” on a method parameter in Java?
  9. What is the use of interface constants?
  10. Why does the behavior of the Integer constant pool change at 127?
  11. Why would one mark local variables and method parameters as “final” in Java? [closed]
  12. Behaviour of final static method
  13. Why would one declare an immutable class final in Java?
  14. java: “final” System.out, System.in and System.err?
  15. final keyword in method parameters [duplicate]
  16. Getting value of public static final field/property of a class in Java via reflection
  17. Java `final` method: what does it promise?
  18. Changing private final fields via reflection
  19. Why are all fields in an interface implicitly static and final?
  20. The final local variable cannot be assigned
  21. How are arrays implemented in java?
  22. Anonymous-Inner classes showing incorrect modifier
  23. What’s the best way to get a Class object for an array type?
  24. Why can final object be modified?
  25. Why defining class as final improves JVM performance?
  26. Is Java guaranteed to inline string constants if they can be determined at compile time
  27. How is concatenation of final strings done in Java?
  28. In Java why this error: ‘attribute value must be constant’?
  29. Initialize final variable before constructor in Java
  30. How to define static constants in a Java enum?

Leave a Comment