mock test question about passing null as method parameter

[Sudarshan Sreenivasan]

class Test {

void someMethod ( Boolean obj ) {
System . out . println ( " Hello Boolean " ) ;
}

void someMethod ( Byte obj ) {
System . out . println ( " Hello Byte " ) ;
}

public static void main ( String args [ ] ) {
new Test ( ) . someMethod ( null ) ;
}
};



Options :

a . Compiles fine but throws an exception at runtime
b . Prints " Hello Boolean " when executed
c . Prints " Hello Byte " when executed
d . Compiler error - method call is ambiguous
e . Compiler error - no method matching someMethod ( null ) found


Output d . Compiler error - method call is ambiguous


Howcome we getting a compiler error when clearly Byte is more specific than Boolean.
Byte extends Number extends Object
Boolean extends Object

Please let me know how it works !!

Thanks

[Chandra Bhatt]

Hi,

Definitely the method call is ambiguous. null can be supplied to Byte
as well as Boolean. No method is more specific than the other to satisfy the
method call passing null as parameter.

sid sree
Howcome we getting a compiler error when clearly Byte is more specific than Boolean.
Byte extends Number extends Object
Boolean extends Object

It is not the way, you select more specific method.

Thanks,

[Sudarshan Sreenivasan]

hi

could you plese tell me what is technique used to find the more specific method because i had come acorss an example with a method(Obejct o) and method (String s)

Stating that method (String s) version is more specific because its lower in the object hierarchy !!

Please tell me where i am going wrong

Thanks

[marc weber]

See our SCJP FAQ: What is a most-specific method?

[Manfred Klug]

Hi sid,

have a look at the following discussion. The example is much more complicated, but it may be helpful.