Let my class name is round. Why I have to write this syntax for dynamic memory alloc. like this........ round x = new round ();

Question

I mean why to use class name. Why can't any other name....??

Answer 1

I'm not sure what you are asking. Why can't you use another class name? Or why do you have to use this syntax?
ClassName varName = new ClassName();

That syntax is just how constructors work in Java. You can also use a factory:
ClassName varName = MyClassFactory.create();

There are some other ways as well (using reflection, etc). Serialization for example.

Most of the others rely on Constructors though.

Answer 2

Yup...you interpreted it right....

but still its not clear to me that why constructor works this way. I mean there must be a reson developers kept the syntax this way...?

I just want that reason.....

please can you explain it to me...😁

Answer 3

Well, sometimes you may have inheritance so you want the left side to be a different type.

For example, HashMap implements Set and you really only care that it's a Set. So you may use this type of declaration:

Set<String> names = new HashSet<>();

The new keyword is what tells the JVM to allocate memory for a new HashSet.

Sometime down the road, you may want to use a different type of Set, for instance, a TreeSet. Then you just have to change one line to change the implementation:

Set<String> names = new TreeSet<>();

Answer 4

okay.....
Now I got it.....thanks.....😄