In Java, a BiPredicate is a functional interface that represents a predicate (a boolean-valued function) that takes two arguments. It's a part of the java.util.function package introduced in Java 8, ...

RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM. - ReactiveX/RxJava ...

BooleanSupplier, LongSupplier, DoubleSupplier LongUnaryOperator, DoubleUnaryOperator, IntUnaryOperator As you can see, the various Java functional interfaces simply provide a somewhat different spin ...