Writing an instance of a class in java

Question

ClassName a = new ClassName1();

What does ClassName and ClassName1 mean? I thought that ClassName had to equal ClassName1.

Hard to tell without more context, but it seems that `ClassName1` is subtype of `ClassName` — rkosegi, Apr 05 '20 at 19:49
It's not really clear what you're trying to do, but I highly doubt "class1" needs to be a subtype of "class". Rather you should be writing `ClassName class1 = new ClassName("class1")`, or similar — OneCricketeer, Apr 06 '20 at 06:45

Antoniossss · Answer 1 · 2020-04-06T06:42:33.303

2

If

public class ClassName1 extends/implements ClassName

than it is perfectly valid.

This is how polimorphism works - you can treat given instance as it would be a solely instance of any of its superclasses or interfaces it implements.

edited Apr 06 '20 at 06:42

answered Apr 05 '20 at 19:49

Antoniossss

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score 0 · Answer 2 · answered Apr 05 '20 at 19:55

ClassName is the type of the variable a, which means for your problem, that a can represents an object of the type ClassName (and any other subclass of it).

So, the sentence ClassName a = new ClassName1() only make sense and is right if the ClassName1 is a subclass of ClassName.

Writing an instance of a class in java

2 Answers2