CODEWITHSUNDEEP
java
Zhang Nick
Zhang Nick

Reputation: 11

the relationship between object and class in java

Alpha.java

class Alpha {
  private void iamprivate() {
    System.out.println("iamprivate");
  }
}

Beta.java

class Beta {
  void accessMethod() {
    Alpha a = new Alpha();
    a.iamprivate();     // illegal
  }
}

A instance of class Alpha should have all the variables and methods of the class.

But, why can not we invoke all the object's methods? Just because some methods are private?

It looks like instances of class don't have the class's private members outside the definition of the class.

Sorry, I am totally beginner. The question may be silly.

Upvotes: 1

Views: 705

Answers (3)

Juned Ahsan
Juned Ahsan

Reputation: 68715

But, why can not we invoke all the object's methods? Just because some methods are private?

Private methods are not exposed to the outside world but you can always call a private method within the class.

It looks like instances of class don't have the class's private members outside the definition of the class.

Class possess all the properties whether they are private/public. It is just that private members are restricted from being accessed outside the class.

Upvotes: 1

An SO User
An SO User

Reputation: 24998

That is because the method is private. These can only be accessed by the methods of Alpha class. If you want to access it in another class, you need to declare it as public.

Read more here: http://docs.oracle.com/javase/tutorial/java/javaOO/accesscontrol.html

Upvotes: 1

Paul Samsotha
Paul Samsotha

Reputation: 208944

Your method is private

private void iamprivate() {

It can be used only inside of your class, not by instances. Change it to public

Upvotes: 1

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