does a java class need a constuctor?

does a java class need a constructor, in this code there does not seem to be any constructor?

Code:

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class CheckingAccount {

  private double balance = 0;
  public void setBalance(double bal) {
      balance = bal;
  };

  public double getBalance(){

      return balance;
  };
}


class Encapsulation {

  public static void main(String args[]) {
      System.out.println("Starting myEncapsulation...");
      CheckingAccount myAccount = new CheckingAccount();
      myAccount.setBalance(40.00);
      System.out.println("Balance = " + myAccount.getBalance());
  }
}

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in the code line

Code:

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checkingaccount myaccount = new checkingaccount();

---

does the checkingaccount() call a function or does it call the class since there is a pari of brackets at the end of the code

If no constructor at all is defined, the compiler will implicitly define one that takes no arguments and does nothing except inline initializations.

thanks for the reply

what is an inline initialisation

what about if no destructor is defined?

in the code line

Code:

---


checkingaccount myaccount = new checkingaccount();

---

does the checkingaccount() call a function or does it call the class since there is a pari of brackets at the end of the code

Again as CornedBee said, it'll call the no-arguments constructor, if you didn't create one, java will do that.
In-line initialization is calling the constructor of the super class and allocating memory for the attributes and function

EDIT: Java doesn't have a "destructor" you can override the "finalize()" method

Actually, by in-line I meant stuff like this:

Code:

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public class Whatever
{
  int i = 100;
}

---

but what ComputerJy said applies too, of course. Except for the allocating memory stuff: memory for the attributes is already allocated by the time the constructor is called, and functions don't take memory.

thanks for the replies guys, it makes sense



can i break the following code

Code:

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checkingaccount myaccount = new checkingaccount();

---

into

Code:

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checkingaccount myaccount ;
myaccount = new checkingaccount();

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If you try it and it works then it's ok to do so.
Yes its ok to do it

thanks for the reply

the superclass is the base class, right?

what attributes and methods does the superclass contain?

in the code

Code:

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checkingaccount myaccount = new checkingaccount();

---

isnt't the constructir returning an address which is assigned to the object myaccount?

or is it the keyword new which is returning the address?

Depends on the super class you are deriving from, if it's nothing (class Object implicitly), read javadoc for more information

The keyword new returns the reference (there's no such thing as raw addresses in Java). The constructor call initializes the object.

thanks guys
makes sense