Which keyword is used in Java to declare a variable whose value cannot change?

In Java, the keyword used to declare a variable whose value cannot change is "final." When a variable is declared as final, it signifies that once it has been assigned a value, it cannot be reassigned to a new value. This is particularly useful for defining constants that should remain fixed after their initial assignment.

For example, if you declare a variable like this:

final int MAX_VALUE = 100;

you cannot later assign a different value to MAX_VALUE. Attempting to do so would lead to a compile-time error. The final keyword enhances code safety and clarity, making it clear to readers that the value of the variable should not be altered.

Other keywords mentioned serve different purposes in Java. "Const" is not a keyword in Java, while "static" defines class-level variables that belong to the class rather than any particular instance. "Constant" is often used in conversation but is not a keyword in Java. Thus, "final" is the appropriate choice for immutable variable declarations.