What are synchronized methods and synchronized statements?
Synchronized blocks place locks for shorter periods than synchronized methods.
Category: Core Java
Are constructors inherited? Can a subclass call the parent’s class constructor? When?
We cannot inherit a constructor. That is, you cannot create a instance of a subclass using a constructor of one of it’s superclasses. One of the main reasons is because you probably don’t want...
Can you write Java code for declaration of multiple inheritance in Java ?
Java’s interface can be used to implement multiple inheritance, with one important difference from c++ way of doing multiple inheritance: the inherited interfaces must be abstract. This obviates the need to choose between different...
How can you achieve Multiple Inheritance in Java?
Java’s interface can be used to implement multiple inheritance, with one important difference from c++ way of doing multiple inheritance: the inherited interfaces must be abstract. This obviates the need to choose between different...
What are the main differences between Java and C++?
Everything is an object in Java( Single root hierarchy as everything gets derived from java.lang.Object). Java does not have all the complicated aspects of C++ ( For ex: Pointers, templates, unions, operator overloading, structures...
What does the “final” keyword mean in front of a variable? A method? A class?
FINAL for a variable : value is constant FINAL for a method : cannot be overridden FINAL for a class : cannot be derived A final variable cannot be reassigned, but it is not...
Name any four methods every Java class will have
Class Object is the root of the class hierarchy. Every class has Object as a superclass. All objects, including arrays, implement the methods of this class. protected Object clone(): Creates and returns a copy...
What are abstract classes, abstract methods?
A class or a method qualified with “abstract” keyword is an abstract class or abstract method. You create an abstract class when you want to manipulate a set of classes through a common interface....
What’s the difference between the == operator and the equals() method? What test does Object.equals()
equals methods checks for the content of the string objects while == checks for the fact that the two String objects point to same memory location ie they are same references. This methods belongs...
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