What's the equivalent of C's "static" keyword in Java?

Question

I want to know what could be the equivalent keyword in java which could perform same function as "Static keyword in C".. I want to do recursion in java, performing same function that a static keyword in C does...

Please help..

Answer 1

C has two entirely different uses of the static keyword, and C++ adds a third use:

// Use 1: declare a variable or function to be local to a given module
// At global scope:
static int global_var;
static void func();

In this case, the global variable global_var and the function void func() can only be accessed inside the file in which they are declared; they cannot be accessed by any other file.

// Use 2: declare a variable inside a function with global scope
void func(void)
{
    static int x;
}

In this case, the variable x is effectively a global variable, in that there is only one instance of it -- multiple calls to func() (including recursive calls) will always access the same variable.

// Use 3 (C++ only): declare a global variable with class scope
class Widget
{
public:
    static int var;
};

In this case, this declares the variable Widget::var as a global variable, but its scope is different. Outside of class member functions, it has to be named as Widget::var; inside class member functions, it can be named as just var. It can also be made protected or private to limit its scope even more.

Now, what are the analogs of these 3 uses in Java?

Case 1 has no direct analog; the closest is declaring objects with package scope, which is done by omitting a public, protected, or private:

class Widget  // Declare a class with package scope
{
    int x;  // Declare a member variable with package scope
    void func() {}  // Declare a member function with package scope
}

In this case, the declared objects are only accessible by classes within the same package; they are not accessible to other packages.

Case 2 also does not have an analog in Java. The closest you can get is by declaring a global variable (that is, a static class variable, since Java doesn't have true global variables in the strictest sense):

class Widget
{
    private static int func_x;
    public static void func()
    {
        // use func_x here in place of 'static int x' in the C example
    }
}

Case 3 is the only case that has a direct analog in Java. In this case, the static keyword serves exactly the same purpose.