Java Articles - Page 381 of 540

The static field variable is a class level variable and it belongs to the class not the class object.So the static field variable is common to all the class objects i.e. a single copy of the static field variable is shared among all the class objects.A program that demonstrates referencing the static field variable after declaration is given as follows:Example Live Demopublic class Demo {    static int a = 7;    static int b = a + 5;    public static void main(String[] args) {       System.out.println("a = " + a);       System.out.println("b = " + ... Read More

The static variable is a class level variable and it is common to all the class objects i.e. a single copy of the static variable is shared among all the class objects.A static method manipulates the static variables in a class. It belongs to the class instead of the class objects and can be invoked without using a class object.The static initialization blocks can only initialize the static instance variables. These blocks are only executed once when the class is loaded.A program that demonstrates this is given as follows:Example Live Demopublic class Demo {    static int x = 10;   ... Read More

Instance variables are initialized using initialization blocks. However, the static initialization blocks can only initialize the static instance variables. These blocks are only executed once when the class is loaded. There can be multiple static initialization blocks in a class that is called in the order they appear in the program.A program that demonstrates a static initialization block in Java is given as follows:Example Live Demopublic class Demo {    static int[] numArray = new int[10];    static {       System.out.println("Running static initialization block.");       for (int i = 0; i < numArray.length; i++) {     ... Read More

An interface contains variables and methods like a class but the methods in an interface are abstract by default unlike a class. An interface extends another interface like a class implements an interface in interface inheritance.A program that demonstrates extending interfaces in Java is given as follows:Example Live Demointerface A {    void funcA(); } interface B extends A {    void funcB(); } class C implements B {    public void funcA() {       System.out.println("This is funcA");    }    public void funcB() {       System.out.println("This is funcB");    } } public class Demo {   ... Read More

A method that accepts a variable number of Object arguments in Java is a form of variable length arguments(Varargs). These can have zero or multiple Object type arguments.A program that demonstrates this is given as follows:Example Live Demopublic class Demo {    public static void Varargs(Object... args) {       System.out.println("Number of Object arguments are: " + args.length);       System.out.println("The Object argument values are: ");       for (Object i : args)       System.out.println(i);    }    public static void main(String args[]) {       Varargs("Apples", "4", "All");       Varargs("Half of", 3, ... Read More

A method with variable length arguments(Varargs) in Java can have zero or multiple arguments. Variable length arguments(Varargs) can also be used with standard arguments However they must be the last argument in the argument list. Moreover, there can only be one variable length argument in the method.A program that demonstrates this is given as follows:Example Live Demopublic class Demo {    public static void Varargs(int i, String... str) {       System.out.println("Number of Vararg are: " + i);       System.out.println("The argument values are: ");       for (String s : str)          System.out.println(s);   ... Read More

A method with variable length arguments(Varargs) in Java can have zero or multiple arguments. Variable length arguments are most useful when the number of arguments to be passed to the method is not known beforehand. They also reduce the code as overloaded methods are not required.A program that demonstrates this is given as follows:Example Live Demopublic class Demo {    public static void Varargs(String... str) {       System.out.println("Number of arguments are: " + str.length);       System.out.println("The argument values are: ");       for (String s : str)          System.out.println(s);    } ... Read More

Method overloading in a class contains multiple methods with the same name but the parameter list of the methods should not be the same. One of these methods can have a long parameter in their parameter list.A program that demonstrates this is given as follows −Example Live Democlass PrintValues {    public void print(int val) {       System.out.println("The int value is: " + val);    }    public void print(long val) {       System.out.println("The long value is: " + val);    } } public class Demo {    public static void main(String[] args) {       ... Read More

A copy constructor can be used to duplicate an object in Java. The copy constructor takes a single parameter i.e. the object of the same class that is to be copied. However, the copy constructor can only be explicitly created by the programmer as there is no default copy constructor provided by Java.A program that demonstrates this is given as follows −Example Live Democlass NumberValue {    private int num;    public NumberValue(int n) {       num = n;    }    public NumberValue(NumberValue obj) {       num = obj.num;    }    public void display() { ... Read More

A class declaration can contain a method that has a parameter in Java. A program that demonstrates this is given as follows:Example Live Democlass Message {    public void messagePrint(String msg) {       System.out.println("The message is: " + msg);    } } public class Demo { public static void main(String args[]) { Message m = new Message(); m.messagePrint("Java is fun"); } }OutputThe message is: Java is funNow let us understand the above program.The Message class is created with a single member ... Read More