Found 9344 Articles for Object Oriented Programming

A constructor should have the name same as the class. Since anonymous inner class has no name, an anonymous inner class cannot have an explicit constructor in Java. But, Java compiler internally creates a constructor for the anonymous class.

Java util package contains collection framework, collection classes, classes related to date and time, event model, internationalization, and miscellaneous utility classes. On importing this package, you can access all these classes and methods.Following table lists out the classes in the collection package.InterfacesDescriptionClassesCollectionCollection Interface represents a group of objects. It is a root interface of collection framework.Abstract CollectionSetIt is a dynamic group of unique elements. It does not store duplicate element.HashSetLinkedHashSetListThey are similar to sets with the only difference that they allow duplicate values in them.StackvectorArrayListLinkedListQueueIt is an arrangement of the type First-In-First-Out (FIFO).First element put in the queue is the ... Read More

An inner class declared without a class name is known as an anonymous inner class. we declare and instantiate them at the same time. In general, they are used whenever you need to override the method of a class or an interface. Syntax AnonymousInner an_inner = new AnonymousInner() { public void my_method() { ........ ........ } }; Example Live Demo abstract class AnonymousInner { public abstract void mymethod(); } public class Outer_class { ... Read More

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. So, you cannot modify a final method from a sub class. The main intention of making a method final would be that the content of the method should not be changed by any outsider. Example public class FinalMethodExample { public final void display(){ System.out.println("Hello welcome to Tutorialspoint"); } public static void main(String args[]){ ... Read More

Java is not dependent on any specific operating system so Java applications cannot depend on the platform dependent native libraries, therefore, instead of those Java provides a set of dynamically loaded libraries that are common to modern operating systems.These libraries provide –Container classes and Regular Expressions.Interfaces for tasks that depend on the hardware of the OS such as network and file access.In case, the underlying platform does not support certain feature of Java then, these libraries surpass that specific feature if needed.

In Java, we can write a class within a method and this will be a local type. Like local variables, the scope of the inner class is restricted to the method.A method-local inner class can be instantiated only within the method where the inner class is defined. The following program shows how to use a method-local inner class.ExampleLive Demopublic class OuterClass {    public void display(){       int num = 23;       class Inner{          public void print() {             System.out.println("This is method inner class "+num);     ... Read More

The Object class of the java.lang package is the root class in Java i.e. It is the super class of every user-defined/predefined class n Java. All objects, including arrays, implement the methods of this class. The reason for this is to have common functionalities such as synchronization, garbage collection, collection support, object cloning for all objects in Java. The class named Class of java.lang package provides a method named getSuperclass() this method returns the Class representing the superclass of the current Class. So, Create a sample concrete class and try to get the name of its super class using this ... Read More

The full form of API is Application Programming Interface. It is a document which gives you the list of all the packages, classes, and interfaces, along with their fields and methods.Using these API’s, the programmer can know how to use the methods, fields, classes, interfaces provided by Java libraries.

Following are the notable differences between inner classes and static inner classes.Accessing the members of the outer classThe static inner class can access the static members of the outer class directly. But, to access the instance members of the outer class you need to instantiate the outer class.Examplepublic class Outer {    int num = 234;    static int data = 300;    public static class Inner{       public static void main(String args[]){          Outer obj = new Outer();          System.out.println(obj.num);          System.out.println(data);       }    } ... Read More

Java is considered to be more dynamic than C or C++ since it is designed to adapt to an evolving environment. Java programs can carry an extensive amount of run-time information that can be used to verify and resolve accesses to objects at run-time.