Question

In C++, a member method can be const if it does not modify the class. For example:

class Foo {
public:
  float getValue() const;
};

Is there something similar I must do in Java classes? How exactly does consting work in Java? (Aside from adding the final keyword before a member variable declaration and initializing it)

Thanks

Answer 1

Although Java lacks a const qualifier, you can achieve some of the same ends with read-only interfaces and immutable types.

So, instead of qualifying a reference as const, you could specify its type to be a read-only interface type.

For example, given these two interfaces:

    public interface A {
       int getValue(); 
    }

    public interface MutableA extends A {
       void setValue( int i );
    }

Then this method’s argument is similar to a const-qualified pointer/reference in C++.

    public void foo( A a )