As import statement allows to use a class without its package qualification, static import allows to access the static members of a class without class qualifications. For Example, to access the static methods you need to call the using class name − Math.sqrt(169); But, using static import you can access the static methods directly. Example Live Demo import static java.lang.Math.*; public class Sample{ public static void main(String args[]){ System.out.println(sqrt(169)); } } Output 13.0

No, java.lang package is a default package in Java therefore, there is no need to import it explicitly. i.e. without importing you can access the classes of this package. If you observe the following example here we haven’t imported the lang package explicitly but, still we are able to calculate the square root of a number using the sqrt() method of the java.lang.Math class. Example Live Demo public class LangTest { public static void main(String args[]){ int num = 100; double result = ... Read More

As per dictionary, abstraction is the quality of dealing with ideas rather than events. For example, when you consider the case of e-mail, complex details such as what happens as soon as you send an e-mail, the protocol your e-mail server uses are hidden from the user. Therefore, to send an e-mail you just need to type the content, mention the address of the receiver, and click send. Abstraction is a process of hiding the implementation details from the user, only the functionality will be provided to the user. In other words, the user will have the information on what ... Read More

Passing Parameters by Value means calling a method with a parameter. Through this, the argument value is passed to the parameter. Example public class SwappingExample { public static void swapFunction(int a, int b) { int c = a+b; System.out.println("Sum of the given numbers is ::"+c); } public static void main(String[] args) { int a = 30; int b = 45; swapFunction(a, b); } } Output Sum of the given numbers is ::75

Recursion is where which a method class itself.Examplepublic class RecursionExample {    private static long factorial(int n) {    if (n == 1)       return 1;    else       return n * factorial(n-1);    }    public static void main(String args[]) {       RecursionExample obj = new RecursionExample();       long result = obj.factorial(5);       System.out.println(result);    } }

Converting a subclass type to a superclass type is known as up-casting.Converting a superclass type to a subclass type is known as down-casting.

Typecasting is converting one data type to another.Up-casting − Converting a subclass type to a superclass type is known as up casting.Exampleclass Super {    void Sample() {       System.out.println("method of super class");    } } public class Sub extends Super {    void Sample() {       System.out.println("method of sub class");    }        public static void main(String args[]) {       Super obj =(Super) new Sub(); obj.Sample();    } }Down-casting − Converting a superclass type to a subclass type is known as downcasting.Exampleclass Super {    void Sample() {     ... Read More

Multiple inheritances lead to ambiguity.For example, if there is a class named Sub and there are two classes Super1 and Super2 and if both contains a method named sample(). And if the class sub inherits both classes Super1 and Super2 then there will be two copies of the sampling method one from each superclass and it is ambiguous to decide which method to be executed.

Association of method call with the method body is known as binding in Java. There are two kinds of binding. Static binding In static binding the method call is bonded with the method body at compile time. This is also known as early binding. This is done using static, private and, final methods. Example class Super{ public static void sample(){ System.out.println("This is the method of super class"); } } Public class Sub extends Super{ Public static void sample(){ ... Read More

You can create an object of the class named Class in two ways −Using new keyword as −Class obj = new Class();Using the forName() method of the class named Class.Class obj = Class.forName("DemoTest");