error- ambiguous reference to method

[Astha Sharma]

class Test
{
void A(int... a){
	System.out.println("in int");
}
void A(float... a){
	System.out.println("in float");
}
void A(double... a){
	System.out.println("in double");
}
public static void main(String[]args)
{
	Test a=new Test();
	a.A(7);
}
}

Why i am getting error "reference to A is ambiguous, both method A(float...) in Test and method A(double...) in Test match" in this code?

[Sebanti Sanyal]

You may find this thread useful.
link

[Astha Sharma]

thanks Sebanti
reading that discussion I concluded that var-args in any case have same priority. It doesn't matter wether it is

method(int... i)

or

method(float... i)

or

method(Integer... i)

with a call

method(int)

all have same priority. Thats why it is ambigous for compiler to predict the call. Am I right?

[Astha Sharma]

but if it is so, the why this is allowed?

class Test
{
void A(Object... a){
	System.out.println("in Object");
}

void A(Integer... a){
	System.out.println("in Integer");
}
public static void main(String[]args)
{
	Test a=new Test();
	a.A(8);
}
}

[Bogdan Todasca]

Hi

For objects there are no concepts like narrowing or widening as there are for primitives but only upcasting/downcasting if the 2 belong to the same hierarchy.
For example, this won't work:

Integer myInteger = 2;
Long myLong = (Long)myInteger;

Long it's NOT an Integer(they both extend Number but there is no direct link between them in the hierarchy) even if long(the primitive) can be seen as an integer through widening.

This won't work neither:

class MyTest{
    public static void main(String ...args){
        testBoxing(2);
    }

    static void testBoxing(Long obj){
        System.out.println("long!");
    }
}

Best,

Astha Sharma wrote:but if it is so, the why this is allowed?

class Test
{
void A(Object... a){
	System.out.println("in Object");
}

void A(Integer... a){
	System.out.println("in Integer");
}
public static void main(String[]args)
{
	Test a=new Test();
	a.A(8);
}
}

[Ratnesh Navlakhe]

In this code
you are overloading the methods with the same name
so the compiler is unable to search for that specific method

and don't use dot(..) in the method arguments .
class Test
{
void A(int a){
System.out.println("in int");
}
void A(float a){
System.out.println("in float");
}
void A(double a){
System.out.println("in double");
}
public static void main(String[]args)
{
Test a=new Test();
a.A(7);
}
}
copy and run it

[Astha Sharma]

no one is answring my question
I am asking that why this

class Test
{
void A(Object... a){
	System.out.println("in Object");
}

void A(Integer... a){
	System.out.println("in Integer");
}
public static void main(String[]args)
{
	Test a=new Test();
	a.A(8);
}
}

is allowed while this

class Test
{
void A(int... a){
	System.out.println("in int");
}
void A(float... a){
	System.out.println("in float");
}
void A(double... a){
	System.out.println("in double");
}
public static void main(String[]args)
{
	Test a=new Test();
	a.A(7);
}
}

or this

class Test
{
void A(int... a){
	System.out.println("in int");
}
void A(Integer... a){
	System.out.println("in float");
}
public static void main(String[]args)
{
	Test a=new Test();
	a.A(7);
}
}

is not allowed?