Conversion question

[Gunjan Kumar]

interface I1 {} interface I2 {}
class Base implements I1 {}
class Sub extends Base implements I2 {}
class Yellow {
public static void main(String args[]) {
Base base = new Sub(); // 1
I1 i1 = base; // 2
Sub sub = (Sub)base; // 3
I2 i2 = (Sub)base; // 4
}}

I have doubt on line 4 . How base is getting assigned to i2 as i see there is no relation between base and I2.

Please explain.

[Nik Arora]

I2 i2 = (Sub)base; // 4

Hi gunjan,
Your casting the base to sub and then passing it to i2 and sub implements interface 2

[Gunjan Kumar]

ok but i thought first i am assigning and then casting .

anyway thanks

[Rick Rangers]

Originally posted by gkcom gk:

Base base = new Sub(); // 1
I1 i1 = base; // 2
Sub sub = (Sub)base; // 3
I2 i2 = (Sub)base; // 4
}}

I have doubt on line 4 . How base is getting assigned to i2

Base is NOT assigned to i2. The OBJECT base is referring to is assigned to i2. This object is of class Sub which implements I2.

Another option would be to cast base to I2:

I2 i2 = (I2) base; // 4

HTH,
Regards,
Rick