The OptionalInt, OptionalLong and OptionalDouble in Java are container objects which may contain a int, long and double value respectively.

The StringTokenizer helps to break a string into tokens with a specified delimiter. In this post, we will learn about StringTokenizer in Java.

A Java DoubleStream is a sequence of double-valued elements that supports sequential and parallel aggregate operations.

Many JDK interfaces were enhanced with default methods in Java 8. In this post we will learn about the default methods in the Java Map interface.

The Apache Commons Lang Validate class in the Apache Commons Lang library helps in validating arguments to a method (or a constructor)

The Apache Commons Lang library provides utility classes and methods. In the post we will learn about the Apache Commons Lang Range class.

In Java 10, the Collectors has static utility methods to return collectors which collect the stream elements into an immutable collection.

In this post we will learn about the various Java Collections Utility methods that operate on collections or return collections.

Collectors collectingAndThen returns a new Collector that adapts a passed Collector to perform a finishing transformation function.

The Apache Commons Lang ComparableUtils has utility methods for translating a Comparable result into a boolean represented as a Predicate.