Why can't Final variables be accessed in a static variables. At the compile time they are simply substituted directly substituted with their values so, they should be allowed to use even in static methods
why is this restriction???
+2
A:
Not all final variables are compile time constants. Only static final variables can be substituted by compiler as compile-time constants. final modifier in certain cases is only used to ensure const-correctness.
And static methods cannot access non-static variables as those variables can have different values for different instances of the same class.
missingfaktor
2010-01-13 19:59:06
+1
A:
If you're asking why a static method cannot access a final instance variable (on the [incorrect] assumption that final member variables are always set to literal or constant values in the code), its because different instances of a class can have different values for the same final instance variable (which can be set, for example, via the constructor). A static method has no knowledge of any particular instance of the class, and could only access static final variables.
danben
2010-01-13 19:59:48
+3
A:
static = in the class.
final = doesn't change it's value (but it is of each instance if it's not static).
By examply you can do:
public class Weird
{
private static long number = System.getTimeInMilis();
private final long created = System.getTimeInMilis();
}
Each time you create a Weird object it will contain a different value for created.
But the value of Weird.number will be the time when the class was loaded.
helios
2010-01-13 19:59:51
A more real example: you can create a "private final list = new ArrayList<...>" and you will not change the reference to the list but the list can add objects when you want.
helios
2010-01-13 20:01:43
...does not change the value *after assignment*. This is compiler enforced, not jvm enforced
Thorbjørn Ravn Andersen
2010-01-13 21:21:52