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Java Articles
Page 284 of 450
How to implement the ObjIntConsumer interface using lambda expression in Java?
The ObjIntConsumer interface is a kind of functional interface and defined in java.util.function package. This functional interface expects an object-valued and int-valued argument as input and does not produce any output. It holds only one functional method, accept(Object, int).Syntax@FunctionalInterface public interface ObjIntConsumer { void accept(T t, int value) }In the below examples, we can implement the ObjIntConsumer interface by using a lambda expression.Example-1import java.util.function.*; public class ObjIntConsumerInterfaceTest1 { public static void main(String args[]) { ObjIntConsumer objIntConsumberObj = (t, value) -> { ...
Read MoreHow to implement ToIntFunction using lambda and method reference in Java?
ToIntFunction is the built-in functional interface defined in java.util.function package. This functional interface expects an argument as input and produces an int-valued result. It can be used as an assignment target for a lambda expression or method reference. The ToIntFunction interface holds only one method, applyAsInt(). This method performs an operation on the given argument and returns the int-valued result.Syntax@FunctionalInterface public interface ToIntFunction { int applyAsInt(T value); }In the below example, we can implement ToIntFunction by using lambda expression and method reference.Exampleimport java.util.function.ToIntFunction; import java.time.LocalDate; public class ToIntFunctionInterfaceTest { public static void main(String[] ...
Read MoreHow to reverse a string using lambda expression in Java?
A String is an object that represents a sequence of characters and immutable in Java. We can reverse a string entered by the user using the charAt() method of String class to extract characters from the string and append them in reverse order to reverse the entered string.In the below example, we need to reverse a string using lambda expression with the help of the Scanner class.Exampleimport java.util.Scanner; interface StringFunc { String func(String n); } public class StringFuncLambdaTest { public static void main(String args[]) { Scanner sc = new Scanner(System.in); StringFunc reverse = (str) -> { // ...
Read MoreHow to serialize a lambda function in Java?
The Serialization is a process for writing the state of an object into a byte stream so that we can transfer it over the network. We can serialize a lambda expression if its target type and its captured arguments have serialized. However, like inner classes, the serialization of lambda expressions is strongly discouraged.In the below example, we can serialize and deserialize a lambda function using a Function interface.Exampleimport java.io.*; import java.util.function.Function; interface MyInterface { void hello(String name); } class MyImpl implements MyInterface { public void hello(String name) { System.out.println("Hello " + name); } } public class SerializeDeSerializeLambdaTest { public static void main(String[] args) ...
Read MoreHow to use IntStream in lambdas and method references in Java?
An IntStream interface extends the BaseStream interface in Java 8. It is a sequence of primitive int-value elements and a specialized stream for manipulating int values. We can also use the IntStream interface to iterate the elements of a collection in lambda expressions and method references.Syntaxpublic interface IntStream extends BaseStreamExampleimport java.util.stream.IntStream; public class StringToIntegerStreamTest { public static void main(String[] args) { String str = "Tutorials Point"; IntStream stream = str.chars(); stream.forEach(element -> System.out.println(((char)element))); // using lambda expression ...
Read MoreHow to use BooleanSupplier in lambda expression in Java?
BooleanSupplier is a functional interface defined in the "java.util.function" package. This interface can be used as an assignment target for a lambda expression or method reference. BooleanSupplier interface has only one method getAsBoolean() and returns a boolean result, true or false.Syntax@FunctionalInterface public interface BooleanSupplier { boolean getBoolean(); }Exampleimport java.util.function.BooleanSupplier; public class BooleanSupplierLambdaTest { public static void main(String[] args) { BooleanSupplier Obj1 = () -> true; BooleanSupplier Obj2 = () -> 5 < 50; // lambda expression BooleanSupplier Obj3 = () -> "tutorialspoint.com".equals("tutorix.com"); System.out.println("Result of Obj1: " + Obj1.getAsBoolean()); ...
Read MoreHow to use FileFilter interface in lambda expression in Java?
A FileFilter is a functional interface from the "java.io" package. It can be used as the assignment target for a lambda expression or method reference. An instance of the FileFilter interface passed to the listFiles() method of the File class. FileFilter interface having one abstract method accept() and it tests whether or not the specified abstract pathname has included in a pathname list.Syntax@FunctionalInterface public interface FileFilterExampleimport java.io.File; import java.io.FileFilter; public class FileFilterTest { public static void main(String[] args) { File dir = new File("C:/Program Files/Java/jdk1.8.0_211"); ...
Read MoreHow to implement PropertyChangeListener using lambda expression in Java?
A PropertyChangeListener is a functional interface from java.beans package. It has one abstract method propertyChange() and gets called when a bound property is changed. This method takes a PropertyChangeEvent argument that has details about an event source and the property that has changed. A PropertyChangeSupport can be used by beans that support bound properties. It can manage a list of listeners and dispatches property change events. The PropertyChangeListener's implementer does the role of an Observer and bean wrapping the PropertyChangeSupport is Observable.Syntaxvoid propertyChange(PropertyChangeEvent evt)Exampleimport java.beans.*; import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.border.*; public class PropertyChangeListenerLambdaTest { public static void main(String [] args) { ...
Read MoreHow to iterate the contents of a collection using forEach() in Java?
Lambda expression is the anonymous representation of a function descriptor of a functional interface. As we know that all collection interfaces like List, Set and Queue use an Iterable as their super interface. Since Java 8, an Iterable interface introduces a new method called forEach(). This method performs an action on the contents of Iterable in the order elements that occur when iterating until all elements have processed.Syntaxvoid forEach(Consumer
Read MoreHow to use BinaryOperator interface in lambda expression in Java?
BinaryOperator is one of a functional interface from java.util.function package and having exactly one abstract method. A lambda expression or method reference uses BinaryOperator objects as their target. BinaryOperator interface represents a function that takes one argument of type T and returns a value of the same type.BinaryOperator Interface contains two static methods, minBy() and maxBy(). The minBy() method returns a BinaryOperator that returns the greater of two elements according to a specified Comparator while the maxBy() method returns a BinaryOperator that returns the lesser of two elements according to a specified Comparator.Syntax@FunctionalInterface public interface BinaryOperator extends BiFunctionExampleimport java.util.function.BinaryOperator; ...
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