java Archives - Page 5 of 6

Thread Synchronization in Java

November 8, 2019November 9, 2018 by manish

When two or more threads try to access the same resource, they need somehow to ensure that the resource will be used by only one thread at a time. The process by which this achive is called Synchronization. Java uses the concept of monitor (also called semaphore) for Synchronization. The monitor allows one thread at … Read more

Thread Priorities in Java

November 8, 2019November 9, 2018 by manish

In java, when two or more than two thread is computing for CPU time, every thread is assigned a priority value. A highest Priority thread get preference over lower priority thread. All Java threads have a priority in the range 1-10. Top priority is 10, lowest priority is 1.Normal priority ie. priority by default … Read more

Main Thread in Java

November 8, 2019November 9, 2018 by manish

In Java programming, when a program begins the first thread that starts running is called main thread. Other threads(child thread) can be spawned from this main thread. When program terminates, the main thread must be the last thread in the program to end. When the main thread stops, the program stops running. Main thread is … Read more

Finally Keyword in Java

November 8, 2019November 3, 2018 by manish

In java exception handling, any code that we want to must be execute put inside the finally block. After the execution of try and catch block, finally block executes. try block must be used with either catch or finally, or with both. Normally when exception occurs then further programs never executes. But either exception occurs … Read more

Java Interfaces

November 8, 2019September 1, 2018 by manish

In Java programming, an interface is a collection of method declaration and constant that one or more class can use. It is syntactically similar to the class but the main difference between class and interface is that class contain method declaration with method body and interface method declares without any body. Syntax of interface:

access specifier   interface InterfaceName {

    type var1 = value;
    type var2 = value;

    .....		
    ....	
    type method1(parameter list);

    type method2(parameter list);
}

access specifier interface InterfaceName {

type var1 = value;

type var2 = value;

.....

....

type method1(parameter list);

type method2(parameter list);

}

Java final keyword

November 8, 2019September 1, 2018 by manish

Final is using for three purpose: final is used to prevent method overriding final is used to prevent inherit a class final is used to make a variable constant final is used to prevent overriding: A method declared as final can’t be overridden.

class A {

    final void show() {
    }
}

class B extends A {

    void show() { //error,   can’t 	override
    }
}

class A {

final void show() {

}

class B extends A {

void show() { //error, can’t override

}

Because show() declared as final, it can’t be overridden in B. If … Read more

Java Abstract class

November 8, 2019August 31, 2018 by manish

Any class that contains one or more abstract method must also be declared abstract. We can declare an abstract class by using the abstract keyword in front of class keyword at the beginning of the class declaration. An abstract method is a method which declares in super class and defines by the associate subclass. To … Read more

Method Overriding in Java

September 17, 2020August 30, 2018 by manish

Method overriding is one of the importance concept in Java Programming. What is Method Overriding? In Inheritance hierarchy when a child class defines exact same method that is available in parent class then the method is called overridden method. The process of creating overridden method is called method overriding.

class Shape {
    void draw() {
        System.out.println("Draw Shape");
    }
}
class Triangle extends Shape {
    void draw() {
        System.out.println("Draw Triangle Shape");
    }
}
class Rectangle extends Shape {
    void draw() {
        System.out.println("Draw Rectangle Shape");
    }
}
class Circle extends Shape {
    void draw() {
        System.out.println("Draw Circle Shape");
    }
}
public class MyClass {
    public static void main(String args[]) {
        Shape shape = new Shape();
        shape.draw();
        Triangle triangle = new Triangle();
        triangle.draw();
        Rectangle rectangle = new Rectangle();
        rectangle.draw();
        Circle circle = new Circle();
        circle.draw();
    }
}

class Shape {

void draw() {

System.out.println("Draw Shape");

}

class Triangle extends Shape {

void draw() {

System.out.println("Draw Triangle Shape");

}

class Rectangle extends Shape {

void draw() {

System.out.println("Draw Rectangle Shape");

}

class Circle extends Shape {

void draw() {

System.out.println("Draw Circle Shape");

}

public class MyClass {

public static void main(String args[]) {

Shape shape = new Shape();

shape.draw();

Triangle triangle = new Triangle();

triangle.draw();

Rectangle rectangle = new Rectangle();

rectangle.draw();

Circle circle = new Circle();

circle.draw();

}

Result

Draw Shape
Draw Triangle Shape
Draw Rectangle Shape
Draw Circle Shape

Draw Shape

Draw Triangle Shape

Draw Rectangle Shape

Draw Circle Shape

We have created … Read more

Java Nested and Inner Class

November 8, 2019August 27, 2018 by manish

In java programming it is possible to define a class within another class, such classes are known as nested class. There are two types of nested classes:- 1. Non-static inner class … Read more

JavaAccess Control (Access modifier)

November 8, 2019August 27, 2018 by manish

There are there types of access modifiers in Java. They are: public private and protected. public: A public data can be accessed by outside of the code in which it is defined. private: A private data can not be accessed by outside of the code in which it is defined. The private data can be … Read more