Raja has Published 806 Answers

How to rethrow an exception in Java?

raja
raja
Published on 13-Jun-2019 15:00:52
Sometimes we may need to rethrow an exception in Java. If a catch block cannot handle the particular exception it has caught, we can rethrow the exception. The rethrow expression causes the originally thrown object to be rethrown.Because the exception has already been caught at the scope in which the ... Read More

What is the importance of the Throwable class and its methods in Java?

raja
raja
Published on 13-Jun-2019 14:38:26
The Throwable class is a superclass of all errors and exceptions in Java. Objects that are instances of this class are thrown by the Java Virtual Machine or can be thrown by a throw statement. Similarly, this class or one of its subclasses can be the argument type in a catch clause.Instances of ... Read More

When to use an abstract class and when to use an interface in Java?

raja
raja
Published on 13-Jun-2019 10:42:13
An interface can be used to define a contract behavior and it can also act as a contract between two systems to interact while an abstract class is mainly used to define default behavior for subclasses, it means that all child classes should have performed the same functionality.When to use ... Read More

Can we create an object of an abstract class in Java?

raja
raja
Published on 12-Jun-2019 15:09:52
No, we can't create an object of an abstract class. But we can create a reference variable of an abstract class. The reference variable is used to refer to the objects of derived classes (subclasses of abstract class).An abstract class means hiding the implementation and showing the function definition to ... Read More

What is a constant and how to define constants in Java?

raja
raja
Published on 12-Jun-2019 12:28:35
A constant is a variable whose value cannot change once it has been assigned. Java doesn't have built-in support for constants.A constant can make our program more easily read and understood by others. In addition, a constant is cached by the JVM as well as our application, so using a ... Read More

Can we declare more than one class in a single Java program?

raja
raja
Published on 12-Jun-2019 08:00:54
A single Java program contains two or more classes, it is possible in two ways in Java.Two Ways of Implementing Multiple Classes in a single Java ProgramNested ClassesMultiple non-nested classesHow the compiler behave with Multiple non-nested classesIn the below example, the java program contains two classes, one class name is ... Read More

How many ways to prevent method overriding in Java?

raja
raja
Published on 12-Jun-2019 07:38:43
Method overriding works because of the run-time method binding feature in Java. So, if we force the java compiler to do static binding for a method then we can prevent that method from being overridden in a derived class.We can prevent method overriding in Java in 3 waysBy making method ... Read More

Why we should follow the naming conventions in Java?

raja
raja
Published on 10-Jun-2019 15:26:25
Naming conventions in Java make programs more understandable by making them easier to read.In Java, class names generally should be nouns, in title case with the first letter of each separate word capitalized. and interface names generally should be adjectives,  in title case with the first letter of each separate ... Read More

What are the differences between default constructor and parameterized constructor in Java?

raja
raja
Published on 10-Jun-2019 14:07:02
Default ConstructorA default constructor is a 0 argument constructor which contains a no-argument call to the super class constructor.To assign default values to the newly created objects is the main responsibility of default constructor.Compiler writes a default constructor in the code only if the program does not write any constructor in ... Read More

What are the different types of classes in Java?

raja
raja
Published on 10-Jun-2019 13:17:02
Types of classes in JavaConcrete classAny normal class which does not have any abstract method or a class that has an implementation of all the methods of its parent class or interface and its own methods is a concrete class.ExampleLive Demopublic class Concrete { // Concrete Class    static int ... Read More
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