Java 8 Tutorial:
Lambda Expressions, Streams, and More
Interested in live training from the
author of these tutorials?
See the upcoming Java 8 and general Java programming courses
in Maryland, co-sponsored by Johns Hopkins Engineering for Professionals. Or,
contact email@example.com for info on
customized courses on Java 8, general Java programming, JSF 2, PrimeFaces, Hadoop, jQuery/Ajax, Android, GWT,
and other J2EE topics taught onsite at your location.
Following is a series of tutorials on the key new features of Java 8. Since each section includes exercises and exercise solutions, this can also be viewed as a self-paced Java 8 training course. The key to learning is not merely reading,
but doing the exercises. After you do each set of exercises, compare your solutions to the ones provided.
These tutorials assume that you already know Java 5 or later, prefarable Java 7; they focus on Java 8 topics
that would not be understandable to those without at least
moderate knowledge of basic syntax, OOP, and data structures in recent Java versions.
If you don't already know the Java language, please see
the Java programming tutorial series.
All the slides (PDF), source code, exercises, and exercise solutions are free for unrestricted use.
Although lambda expressions are not quite real functions, they are close enough for most purposes, and have very
succinct syntax that looks like Scala anonymous functions (minus the type declarations). Although it hardly makes
Java into Lisp, lambdas support a definite functional programming style that is long overdue in Java.
Streams are wrappers around collections that use lambdas pervasively. They support many operations that use lambdas, including "map", "reduce", "filter", and "forEach". They also support lazy evaluation, so if you map firstName over Employees, filter ones that start with "P", then choose the first, it really only maps and filters until the
first match. Streams can also be parallel, so that the operations are automatically done concurrently, without any explicit multithreading code.
Taken together, lambdas and streams result in by far the biggest change to Java programming since at least 2004, when generics and annotations were added to the language.
Looking for short hands-on training courses on Java 8, general Java programming, JSF 2.2, PrimeFaces,
Android development, or other Java-related topics
taught at your company? The courses are taught by Marty Hall,
an experienced instructor, developer, speaker, and well-known Java EE author, and the creator of this tutorial series.
For more information, see the JSF and PrimeFaces training course page or
contact Marty to arrange a course
at your location. Courses are available in any country, and have been given in N. America,
Central America, Europe, Asia, and Australia. Distinctive features of Marty's training:
Experienced instructor who can answer tough questions and show best practices.
Marty & Java inventor James Gosling at
With the big training vendors, you don't even know
the instructor's name before the class begins, much less their credentials.
Marty is an experienced real-world developer, award-winning
instructor, conference speaker on servlets and JSP (including five
times at JavaOne), and author of six popular J2EE books
from Prentice Hall and Sun Microsystems Press.
Core Servlets & JavaServer
Pages is the most popular servlet and JSP book internationally,
with translations in Bulgarian, Chinese (both traditional
and simplified script), Czech, French,
German, Hebrew, Japanese, Korean, Macedonian, Polish, Portuguese, Russian and Spanish.
Marty also teaches in the Johns Hopkins University part-time graduate program
in Computer Science, where he directs the Java and Web-related concentration area.
Click here for more details.
Marty has taught J2EE training courses in
Canada, Australia, Japan, Puerto Rico, Mexico, India, Cambodia, Norway,
the Philippines, and dozens of US venues.
Clients for on-site Java courses include Symantec, VeriSign, the NY Stock Exchange (SIAC), State Farm Insurance,
General Motors, Hewlett Packard, Lexmark International, TransCanada Pipelines, Raytheon, Learjet, Sikorsky,
Los Alamos National Labs, Genomica, the U.S. Navy, General
Dynamics, Banco Popular, Titan Corporation, the University of Michigan,
Context Integration, the University of Utah Hospital, ESI, SAIC, NSA, CIA, and many others.
Click here for a longer list.
No using your developers as guinea pigs!
Flexible schedules. Courses are available in any city worldwide, and have been taught in dozens
of US venues and 9 other countries. However, Maryland-area companies have extra flexibility in the course schedules,
since Marty is local to Maryland. In addition to the full-day courses offered in all locations, Maryland companies can book the courses in the
late afternoons or early evenings. Even weekends are possible! For example, Marty has done about a dozen Maryland courses that met once or twice a
week from 4:30-6:30 pm (or similar) so that the students did not lose billable hours.
Course materials developed by the instructor.
Marty personally developed all of
his own materials, much of it based on his best-selling books. They thoroughly cover
the basics, introduce advanced topics, include many meaty code examples, and show plenty of
live running applications. They also discuss best practices, design strategies,
and efficiency issues. Most of the big
training vendors hire someone to create the course materials, then bring in some
inexperienced flunky to regurgitate them to the class.
Public (open-enrollment) training courses
Onsite courses are cheaper and more convenient for organizations that
have medium to large sized groups of developers. But, in order to serve
organizations with only one or two developers that need training, coreservlets.com
periodically offers public versions of some of the most popular courses.
The next public offerings will be on Java 7 programming, new features in Java 8, Android programming,
Web application development with JSF2, PrimeFaces, Big-Data Apps with Hadoop, Rich Internet Applications with Ajax (and jQuery), GWT programming,
Hadoop, Java EE programming with Spring, Java persistence with Hibernate and JPA,
and Web Services (RESTful and SOAP-based).
The 2013 courses are co-sponsored by Johns Hopkins Engineering for Professionals
and will be held at JHU/Dorsey in Elkridge Maryland (5 minutes from BWI airport).
Click here for details.
A variety of complementary course offerings.
Ads for Marty at GIDS conference in India
Marty personally teaches the following courses (click for detailed course descriptions):
Need some special topics or a
customized mix of topics?
In addition, Marty reviews/edits courses taught by colleagues. These courses are developed by experts who
work daily with the technologies, and the materials are thoroughly reviewed
by Marty. Course topics include:
Want a class on JSF 2 or Spring or Hadoop, but need some
review of basic Java first? No problem. Want to move extra fast because your
developers are experienced? Piece of cake. Need to combine some
basic JSF topics with thorough coverage of PrimeFaces? Just say the word. Want an Ajax and jQuery
Simply let us know. Want training on GWT, but need a review of basic server-side Java techniques
first? Tell us what you need.
Every onsite course is fully customized to the needs and backgrounds of your developers.
Marty's public training courses
are typically at least 10% cheaper than the canned courses
from the big training vendors. And his courses include a textbook,
a bound student notebook, exercises, exercise solutions, and all
necessary software (for onsite courses).
Onsite courses at your location are even cheaper, since there
are no venue rental costs. Plus, your developers don't have to pay travel costs.
The PDF files in this tutorial contain the complete text of the original
PowerPoint files, so if your goal is learning this technology, just stick
with this tutorial. However, as a service to instructors teaching
full-semester courses at accredited universities, coreservlets.com
will release the original PowerPoint files for free. Please
see the instructor materials page