LongSupplier is a built-in functional interface from java.util.function package. This interface doesn’t expect any input but produces a long-valued output. Since LongSupplier is a functional interface, it can be used as an assignment target for lambda expression and method reference and contains only one abstract method: getAsLong().Syntax@FunctionalInterface public interface LongSupplier {  long getAsLong(); }Example of Lambda Expressionimport java.util.function.LongSupplier; ... Read More

LongPredicate is a functional interface defined in java.util.function package. This interface can be used mainly for evaluating an input of type long and returns an output of type boolean. LongPredicate can be used as an assignment target for a lambda expression or method reference. It contains one abstract method: test() and three default methods: and(), negate() ... Read More

IntBinaryOperator is a functional interface in Java 8 from java.util.function package. This interface expects two parameters of type int as input and produces an int type result. IntBinaryOperator can be used as an assignment target for a lambda expression or method reference. It contains only one abstract method: applyAsInt().Syntax@FunctionalInterface public interface IntBinaryOperator {  int applyAsInt(int left, int right) ... Read More

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 ... Read More

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 ... Read More

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 ... Read More

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; ... Read More

A functional interface is a special kind of interface with exactly one abstract method in which lambda expression parameters and return types are matched. It provides target types for lambda expressions and method references.Rules for a functional interfaceA functional interface must have exactly one abstract method.A functional interface has any number of ... Read More

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; ... Read More

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 { ... Read More