Functional Programming in Java

@FunctionalInterface public interface Supplier<T> { /** * Gets a result. * * @return a result */ T get(); } class Test { public static void main(String[] args) { Supplier<String> supplier = () -> “Java”; System.out.println(supplier.get()); } } Output: Java class User { private String name; private String username; private String membershipType; private String address; public…

@FunctionalInterface public interface BinaryOperator<T> extends BiFunction<T,T,T> { /** * Returns a {@link BinaryOperator} which returns the lesser of two elements * according to the specified {@code Comparator}. * * @param <T> the type of the input arguments of the comparator * @param comparator a {@code Comparator} for comparing the two values * @return a {@code…

@FunctionalInterface public interface UnaryOperator<T> extends Function<T, T> { /** * Returns a unary operator that always returns its input argument. * * @param <T> the type of the input and output of the operator * @return a unary operator that always returns its input argument */ static <T> UnaryOperator<T> identity() { return t -> t;…

@FunctionalInterface public interface BiFunction<T, U, R> { /** * Applies this function to the given arguments. * * @param t the first function argument * @param u the second function argument * @return the function result */ R apply(T t, U u); /** * Returns a composed function that first applies this function to *…

@FunctionalInterface public interface Function<T, R> { /** * Applies this function to the given argument. * * @param t the function argument * @return the function result */ R apply(T t); /** * Returns a composed function that first applies the {@code before} * function to its input, and then applies this function to the…

@FunctionalInterface public interface BiPredicate<T, U> { /** * Evaluates this predicate on the given arguments. * * @param t the first input argument * @param u the second input argument * @return {@code true} if the input arguments match the predicate, * otherwise {@code false} */ boolean test(T t, U u); /** * Returns a…

@FunctionalInterface public interface Predicate<T> { /** * Evaluates this predicate on the given argument. * * @param t the input argument * @return {@code true} if the input argument matches the predicate, * otherwise {@code false} */ boolean test(T t); /** * Returns a composed predicate that represents a short-circuiting logical * AND of this…

@FunctionalInterface public interface BiConsumer<T, U> { /** * Performs this operation on the given arguments. * * @param t the first input argument * @param u the second input argument */ void accept(T t, U u); /** * Returns a composed {@code BiConsumer} that performs, in sequence, this * operation followed by the {@code after}…

@FunctionalInterface public interface Consumer<T> { /** * Performs this operation on the given argument. * * @param t the input argument */ void accept(T t); /** * Returns a composed {@code Consumer} that performs, in sequence, this * operation followed by the {@code after} operation. If performing either * operation throws an exception, it is…

Java has evolved over the years to support functional programming, which is a programming paradigm that emphasizes writing code in terms of functions. In Java, functional programming is made possible with the help of functional interfaces, which are interfaces that define a single abstract method. Functional interfaces can be implemented using lambda expressions or method…

Lambda expressions are one of the most significant additions to the Java programming language in recent years. They were introduced in Java 8 and are a way to write more concise and expressive code. Lambda expressions allow you to define and pass around blocks of code, known as functional interfaces, making it easier to write…