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Java Articles
Page 169 of 450
How to implement Function<T, R> interface with lambda expression in Java?\\n
Function interface is a functional interface from java.util.function package. This interface expects one argument as input and produces a result. Function interface can be used as an assignment target for a lambda expression or method reference. It contains one abstract method: apply(), two default methods: andThen() and compose() and one static method: identity().Syntax@FunctionalInterface public interface Function { R apply(T t); }Exampleimport java.util.function.Function; public class FunctionTest { public static void main(String[] args) { Function f1 = i -> i*4; // lambda System.out.println(f1.apply(3)); Function f2 = i -> i+4; // lambda ...
Read MoreHow to implement DoubleSupplier using lambda and method reference in Java?
DoubleSupplier interface is a built-in functional interface defined in java.util.function package. This functional interface doesn’t expect any input but produces a double-valued output. DoubleSupplier interface can be used as an assignment target for lambda expression and method reference. This interface contains only one abstract method: getAsDouble().Syntax@FunctionalInterface public interface DoubleSupplier { double getAsDouble(); }Example of Lambda Expressionimport java.util.concurrent.ThreadLocalRandom; import java.util.function.DoubleSupplier; public class DoubleSupplierLambdaTest { public static void main(String args[]) { DoubleSupplier getRandomDouble = () -> { // lambda expression double doubleVal = ThreadLocalRandom.current().nextDouble(0000, 9999); return Math.round(doubleVal); }; ...
Read MoreHow to create our own/custom functional interface in Java?\\n
The functional interface is a simple interface with only one abstract method. A lambda expression can be used through a functional interface in Java 8. We can declare our own/custom functional interface by defining the Single Abstract Method (SAM) in an interface.Syntaxinterface CustomInterface { // abtstact method }Example@FunctionalInterface interface CustomFunctionalInterface { void display(); } public class FunctionInterfaceLambdaTest { public static void main(String args[]) { // Using Anonymous inner class CustomFunctionalInterface test1 = new CustomFunctionalInterface() { public void display() { System.out.println("Display using Anonymous inner class"); ...
Read MoreHow to implement ObjLongConsumer<T> interface using lambda expression in Java?
ObjLongConsumer is a functional interface from java.util.function package. This interface accepts an object-valued and long-valued argument as input but doesn't produce any output. ObjLongConsumer can be used as an assignment target for lambda expression and method reference and contains only one abstract method: accept().Syntax@FunctionalInterface public interface ObjLongConsumer { void accept(T t, long value) }Exampleimport java.util.function.ObjLongConsumer; public class ObjLongConsumerTest { public static void main(String[] args) { ObjLongConsumer olc = (employee, number) -> { // lambda expression if(employee != null) { System.out.println("Employee Name: " + employee.getEmpName()); ...
Read MoreHow to implement LongFunction<R> using lambda and method reference in Java?
LongFunction is an in-built functional interface defined in java.util.function package. This functional interface expects a long-valued parameter as input and produces a result. LongFunction interface can be used as an assignment target for a lambda expression or method reference. It contains only one abstract method: apply().Syntax@FunctionalInterface public interface LongFunction { R apply(long value) }Exampleimport java.util.function.LongFunction; public class LongFunctionTest { public static void main(String[] args) { LongFunction function1 = (long i) -> { // lambda expression return i + i; }; System.out.println("Using Lambda Expression: " + function1.apply(10)); LongFunction ...
Read MoreHow to implement LongBinaryOperator using lambda and method reference in Java?
LongBinaryOperator is a part of the functional interface from java.util.function package. This functional interface expects two parameters of type long as the input and produces a long type result. LongBinaryOperator interface can be used as an assignment target for a lambda expression or method reference. It contains only one abstract method, applyAsLong().Syntax@FunctionalInterface public interface LongBinaryOperator { long applyAsLong(long left, long right) }Example of Lambda Expressionimport java.util.function.LongBinaryOperator; public class LongBinaryOperatorTest1 { public static void main(String[] args) { LongBinaryOperator multiply = (a, b) -> { // lambda expression return a*b; }; long a = ...
Read MoreHow to implement IntConsumer using lambda and method reference in Java?\\n
IntConsumer interface is a functional interface from java.util.function package in Java 8. This interface accepts a single int-valued argument as input but doesn't produce any output. Since it is a functional interface, it can be used as an assignment target for a lambda expression or method reference. It contains one abstract method: accept() and one default method: andThen().Syntax@FunctionalInterface public interface IntConsumer { void accept(int value); }Example of Lambda Expressionimport java.util.function.IntConsumer; public class IntConsumerTest1 { public static void main(String[] args) { IntConsumer displayNextInt = i -> System.out.println("Next Int Value: " + (i+1)); // lambda IntConsumer displaySquare = ...
Read MorePrint all permutation of a string using ArrayList in Java
In this problem, we are given a string of size n and we have to print all permutations of the string. But this time we have to print this permutation using ArrayList.Let’s take an example to understand the problem -Input − string = ‘XYZ’Output − XYZ, XZY, YXZ, YZX, ZXY, ZYXTo solve this problem, we will be generating all permutations of the character of the string. We will use a recursive function and will return arrayList.ExampleThe following is ArrayList implementation of the algorithm − Live Demoimport java.util.ArrayList; public class Main{ static void printArrayList(ArrayList combo) { combo.remove(""); ...
Read MorePreconditions - Java
Precondition to check if the list passed as parameter is empty or not. Let us see an example −Examplepublic void my_fun(List myList){ if (myList == null){ throw new IllegalArgumentException("List is null"); } if (myList.isEmpty()){ throw new IllegalArgumentException("List is empty"); } my_fun(myList); }A void function named ‘my_fun’ is defined that takes a list of objects as its parameters. If the list is null, it prints the relevant message. If the list has no elements in it, a specific message is displayed. The function is called by passing the list as ...
Read MoreKilling threads in Java
Example Live Demopublic class Main{ static volatile boolean exit = false; public static void main(String[] args){ System.out.println("Starting the main thread"); new Thread(){ public void run(){ System.out.println("Starting the inner thread"); while (!exit){ } System.out.println("Exiting the inner thread"); } }.start(); try{ Thread.sleep(100); } catch (InterruptedException e){ ...
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