How do you use wait and notify?

How do you use wait and notify?

There are two ways of notifying waiting threads.

1. 4.1. notify() For all threads waiting on this object’s monitor (by using any one of the wait() method), the method notify() notifies any one of them to wake up arbitrarily.
2. 4.2. notifyAll() This method simply wakes all threads that are waiting on this object’s monitor.

What is the difference between wait () notify () and notifyAll ()?

In case of multiThreading notify() method sends the notification to only one thread among the multiple waiting threads which are waiting for lock. While notifyAll() methods in the same context sends the notification to all waiting threads instead of single one thread.

Which method Cannot be overridden?

A method declared final cannot be overridden. A method declared static cannot be overridden but can be re-declared. If a method cannot be inherited, then it cannot be overridden. A subclass within the same package as the instance’s superclass can override any superclass method that is not declared private or final.

Can we override wait () and notify () methods?

wait and notify are declared final in object class and hence cannot be overridden.

Can we inherit final method in Java?

No, we cannot override a final method in Java. The final modifier for finalizing the implementations of classes, methods, and variables. We can declare a method as final, once you declare a method final it cannot be overridden.

Can main method be final?

Yes, we can declare the main () method as final in Java. The compiler does not throw any error. The main use of the final method in Java is they are not overridden. We can not override final methods in subclasses.

Are private methods final?

So, to answer question 2, yes, all compilers will treat private methods as final . The compiler will not allow any private method to be overridden. Likewise, all compilers will prevent subclasses from overriding final methods.

Can you inherit a final class?

The main purpose of using a class being declared as final is to prevent the class from being subclassed. If a class is marked as final then no class can inherit any feature from the final class. You cannot extend a final class.

Can Final classes be instantiated?

You can instantiate a final class just like any other non-abstract class. The only limitation is that you cannot create subclasses of a final class.

How do you prevent a class from inheritance?

You can prevent a class from being subclassed by using the final keyword in the class’s declaration. Similarly, you can prevent a method from being overridden by subclasses by declaring it as a final method. An abstract class can only be subclassed; it cannot be instantiated.

Can constructor be private?

Yes, we can declare a constructor as private. If we declare a constructor as private we are not able to create an object of a class. We can use this private constructor in the Singleton Design Pattern.

Why is constructor declared private?

The use of private constructor is to serve singleton classes. Using private constructor we can ensure that no more than one object can be created at a time. By providing a private constructor you prevent class instances from being created in any place other than this very class.

What is the purpose of private constructor?

Private constructors are used to prevent creating instances of a class when there are no instance fields or methods, such as the Math class, or when a method is called to obtain an instance of a class. If all the methods in the class are static, consider making the complete class static.

Can constructor be overridden?

Constructor looks like method but it is not. It does not have a return type and its name is same as the class name. But, a constructor cannot be overridden. If you try to write a super class’s constructor in the sub class compiler treats it as a method and expects a return type and generates a compile time error.

Can you have 2 constructors in Java?

There can be multiple constructors in a class. However, the parameter list of the constructors should not be same. This is known as constructor overloading.

Can constructor be static?

No, we cannot define a static constructor in Java, If we are trying to define a constructor with the static keyword a compile-time error will occur. In general, static means class level. We need to assign initial values for an instance variable we can use a constructor.

Can private constructor class inherited?

What is Private Constructor? If a class has one or more private constructor and no public constructor then other classes are not allowed to create instance of this class; this means you can neither create the object of the class nor can it be inherited by other classes.