Java Articles - Page 192 of 745

DoubleBinaryOperator is a functional interface defined in java.util.function package. It accepts two parameters of type double as input and produces another double value as a result. DoubleBinaryOperator interface can be used as an assignment target for a lambda expression or method reference and has only one abstract method applyAsDouble().Syntax@FunctionalInterface public interface DoubleBinaryOperator {  double applyAsDouble(double left, double right); }Example-1import java.util.function.DoubleBinaryOperator; public class DoubleBinaryOperatorTest {    public static void main(String args[]) {       // using lambda expression       DoubleBinaryOperator sum = (d1, d2) -> d1 + d2;       DoubleBinaryOperator mul = (d1, d2) -> d1 * d2;       DoubleBinaryOperator div = ... Read More

In Java, as we know, Collections are one of the most important concepts that make Java a powerful language in itself. It's the support of collections in Java that makes it support any type of data in a convenient and efficient way, along with possible CRUD operations over them. But on the same phase, when collections get exposed to a multi-threading its performance gets somewhat degraded because somewhere collections lack the support for a multi-threading environment. To overcome this limitation, Java introduces Concurrent Collections, which not only overcome the multi-threading environment limitation but also enhance Java to perform with multiple ... Read More

The javafx.event package provides a framework for Java FX events. The Event class serves as the base class for JavaFX events and associated with each event is an event source, an event target, and an event type. An ActionEvent widely used when a button is pressed.In the below program, we can implement an ActionEvent for a button by using method reference.Exampleimport javafx.application.*; import javafx.beans.property.*; import javafx.event.*; import javafx.scene.*; import javafx.scene.control.*; import javafx.scene.layout.*; import javafx.stage.*; import javafx.scene.effect.*; public class MethodReferenceJavaFXTest extends Application {    private Label label;    public static void main(String[] args) {       launch(args);    }    @Override    public void start(Stage primaryStage) {   ... Read More

IntPredicate interface is a built-in functional interface defined in java.util.function package. This functional interface accepts one int-valued argument as input and produces a boolean value as an output. This interface is a specialization of the Predicate interface and used as an assignment target for a lambda expression or method reference. It provides only one abstract method, test ().Syntax@FunctionalInterface public interface IntPredicate {  boolean test(int value); }Example for Lambda Expressionimport java.util.function.IntPredicate; public class IntPredicateLambdaTest {    public static void main(String[] args) {       IntPredicate intPredicate = (int input) -> {   // lambda expression          if(input == 100) {     ... Read More

This character class \p{javaLowerCase} matches lower case letters. This class matches the characters which returns true when passed as a parameter to the isLowerCase() method of the java.lang.Character class.Example 1 Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample {    public static void main(String args[]) {       //Reading String from user       System.out.println("Enter a string");       Scanner sc = new Scanner(System.in);       String input = sc.nextLine();       //Regular expression       String regex = "[\p{javaLowerCase}]";       //Compiling the regular expression       Pattern pattern = ... Read More

This class matches white space characters. i.e. \t, , \x, 0B, \f, \r.Example 1 Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class SpaceCharacters {    public static void main(String args[]) {       //Reading String from user       System.out.println("Enter a string");       Scanner sc = new Scanner(System.in);       String input = sc.nextLine();       //Regular expression       String regex = "[\p{Space}]";       //Compiling the regular expression       Pattern pattern = Pattern.compile(regex);       //Retrieving the matcher object       Matcher matcher = pattern.matcher(input);   ... Read More

This class matches hexa-decimal characters i.e. [0-9a-fA-F].Example 1 Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class SpaceCharacters {    public static void main(String args[]) {       //Reading String from user       System.out.println("Enter a string");       Scanner sc = new Scanner(System.in);       String input = sc.nextLine();       //Regular expression       String regex = "[\p{XDigit}]";       //Compiling the regular expression       Pattern pattern = Pattern.compile(regex);       //Retrieving the matcher object       Matcher matcher = pattern.matcher(input);       int count = 0; ... Read More

If you want to specify the number of occurrences while constructing a regular expression you can use quantifiers. Java supports three types of quantifiers namely: greedy quantifiers, reluctant quantifiers and possessive quantifiers.Greedy quantifiers − Greedy quantifiers are the default quantifiers. A greedy quantifier matches as much as possible from the input string (longest match possible) if match not occurred it leaves the last character and matches again.Exampleimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Test {    public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("Enter input text: ");     ... Read More

This class matches all the printable characters.Example 1 Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class PrintableCharacters {    public static void main(String args[]) {       //Reading String from user       System.out.println("Enter a string");       Scanner sc = new Scanner(System.in);       String input = sc.nextLine();       //Regular expression       String regex = "[\p{Print}]";       //Compiling the regular expression       Pattern pattern = Pattern.compile(regex);       //Retrieving the matcher object       Matcher matcher = pattern.matcher(input);       int count = 0; ... Read More

This class matches all visible characters i.e. alphabets, digits, punctuation marks.Example 1 Live Demoimport java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class VisiblieCharacters {    public static void main(String args[]) {       //Reading String from user       System.out.println("Enter a string");       Scanner sc = new Scanner(System.in);       String input = sc.nextLine();       //Regular expression       String regex = "[\p{Graph}]";       //Compiling the regular expression       Pattern pattern = Pattern.compile(regex);       //Retrieving the matcher object       Matcher matcher = pattern.matcher(input);       ... Read More