Posts Tagged ‘Java8’
[DevoxxUS2017] Java Puzzlers NG S02: Down the Rabbit Hole by Baruch Sadogursky and Viktor Gamov
At DevoxxUS2017, Baruch Sadogursky and Viktor Gamov, from JFrog and Hazelcast respectively, entertained attendees with a lively exploration of Java 8 and 9 puzzlers. Known for their engaging style, Baruch, a Developer Advocate, and Viktor, a Senior Solution Architect, presented complex coding challenges involving streams, lambdas, and Optionals. Their session combined humor, technical depth, and audience interaction, offering valuable lessons for Java developers. This post examines the key themes of their presentation, highlighting strategies to navigate Java’s intricacies.
Decoding Java 8 Complexities
Baruch Sadogursky and Viktor Gamov kicked off with a series of Java 8 puzzlers, focusing on streams and lambdas. They presented scenarios where seemingly simple code led to unexpected outcomes, such as subtle bugs in stream operations. Baruch emphasized the importance of understanding functional programming nuances, using examples to illustrate common pitfalls. Their interactive approach, with audience participation, made complex concepts accessible and engaging.
Navigating Java 9 Features
Transitioning to Java 9, Viktor explored new puzzlers involving modules and CompletableFutures, highlighting how these features introduce fresh challenges. He demonstrated how the module system can lead to compilation errors if misconfigured, urging developers to read documentation carefully. Their examples, drawn from real-world experiences at JFrog and Hazelcast, underscored the need for precision in adopting Java’s evolving features.
Tools for Avoiding Pitfalls
Baruch and Viktor stressed the role of tools like IntelliJ IDEA in catching errors early, noting how its inspections highlight potential issues in lambda and stream usage. They advised against overusing complex constructs, advocating for simplicity to avoid “WTF” moments. Their practical tips, grounded in their extensive conference-speaking experience, encouraged developers to leverage IDEs and documentation to write robust code.
Community Engagement and Resources
Concluding with a call to action, Baruch and Viktor invited developers to contribute puzzlers to JFrog’s puzzlers initiative, fostering community-driven learning. They shared resources, including their slide deck and blog posts, encouraging feedback via Twitter. Their enthusiasm for Java’s challenges inspired attendees to dive deeper into the language’s intricacies, embracing both its power and pitfalls.
Links:
[DevoxxFR2015] Harnessing Java 8: Building Real-Time Applications
Trisha Gee, a Java Champion and Developer Advocate at JetBrains, showcased the power of Java 8 at Devoxx France 2015 by live-coding a real-time dashboard application. With extensive experience in high-performance Java systems, Trisha demonstrated how streams, lambdas, and the new date/time API can create robust, end-to-end applications using core Java libraries.
Crafting a Real-Time Dashboard
Trisha kicked off by building a JavaFX-based dashboard that consumed a high-velocity data feed, simulating Twitter sentiment analysis. She leveraged Java 8 streams to process collections efficiently, transforming raw data into meaningful insights. Lambdas simplified code, replacing verbose loops with concise expressions. Her demo highlighted real-time updates, with the dashboard dynamically rendering mood data.
This approach, Trisha emphasized, showcases Java 8’s expressiveness.
Streamlining Data Manipulation
Using streams, Trisha demonstrated filtering and aggregating data to display sentiment trends. The joining collector automatically formatted outputs, eliminating manual string manipulation. She also touched on the new date/time API, ensuring precise temporal handling. Despite a glitch requiring a restart, the dashboard successfully visualized real-time Twitter data, proving Java 8’s suitability for dynamic applications.
Her live coding, Trisha noted, demystifies complex features.
JavaFX for Modern UIs
Trisha integrated JavaFX to create a responsive UI, binding data to visual components. She contrasted fake and real mood services, showing how streams handle both seamlessly. Q&A was limited due to time, but she shared a comprehensive resource page, including WebSocket and JavaFX references, encouraging further exploration.
This session positions Java 8 as a versatile tool for modern development.
Links:
[DevoxxBE2013] Part 1: Thinking Functional Style
Venkat Subramaniam, an award-winning author and founder of Agile Developer, Inc., guides developers through the paradigm shift of functional programming on the JVM. Renowned for Functional Programming in Java and his global mentorship, Venkat uses Java 8, Groovy, and Scala to illustrate functional tenets. His session contrasts imperative statements with composable expressions, demonstrating how to leverage lambda expressions and higher-order functions for elegant, maintainable code.
Functional programming, Venkat posits, transcends syntax—it’s a mindset fostering immutability and data flow. Through practical examples, he showcases Groovy’s idiomatic functional constructs and Scala’s expression-driven purity, equipping attendees to rethink application design.
Functional Principles and Expressions
Venkat contrasts statements—imperative, mutation-driven blocks—with expressions, which compute and return values. He demos a Java 8 stream pipeline, transforming data without side effects, versus a loop’s mutability.
Expressions, Venkat emphasizes, enable seamless composition, fostering cleaner, more predictable codebases.
Groovy’s Functional Idioms
Groovy, though not purely functional, excels in functional style, Venkat illustrates. He showcases collect and findAll for list transformations, akin to Java 8 streams, with concise closures.
These idioms, he notes, simplify data processing, making functional patterns intuitive for Java developers.
Scala’s Expression-Driven Design
Scala’s expression-centric nature shines in Venkat’s examples: every construct returns a value, enabling chaining. He demos pattern matching and for-comprehensions, streamlining complex workflows.
This purity, Venkat argues, minimizes state bugs, aligning with functional ideals.
Higher-Order Functions and Composition
Venkat explores higher-order functions, passing lambdas as arguments. A Groovy example composes functions to filter and map data, while Scala’s currying simplifies partial application.
Such techniques, he asserts, enhance modularity, enabling parallelization for performance-critical tasks.
Practical Adoption and Parallelization
Venkat advocates starting with small functional refactors, like replacing loops with streams. He demos parallel stream processing in Java 8, leveraging multi-core CPUs.
This pragmatic approach, he concludes, bridges imperative habits with functional elegance, boosting scalability.
Links:
[DevoxxBE2013] Lambda: A Peek Under the Hood
Brian Goetz, Java Language Architect at Oracle, offers an illuminating dissection of lambda expressions in Java SE 8, transcending syntactic sugar to reveal the sophisticated machinery powering this evolution. Renowned for Java Concurrency in Practice and leadership in JSR 335, Brian demystifies lambdas’ implementation atop invokedynamic from Java SE 7. His session, eschewing introductory fare, probes the VM’s strategies for efficiency, contrasting naive inner-class approaches with optimized bootstrapping and serialization.
Lambdas, Brian asserts, unlock expressive potential for applications and libraries, but their true prowess lies in performance rivaling or surpassing inner classes—without the bloat. Through benchmarks and code dives, he showcases flexibility and future-proofing, underscoring the iterative path to a robust design.
From Syntax to Bytecode: The Bootstrap Process
Brian traces lambdas’ lifecycle: source code desugars to invokedynamic callsites, embedding a “recipe” for instantiation. The bootstrap method, invoked once per callsite, crafts a classfile dynamically, caching for reuse.
This declarative embedding, Brian illustrates, avoids inner classes’ per-instance overhead, yielding leaner bytecode and faster captures—non-capturing lambdas hit 1.5x inner-class speeds in early benchmarks.
Optimization Strategies and Capture Semantics
Capturing lambdas, Brian explains, leverage local variable slots via synthetic fields, minimizing allocations. He contrasts “eager” (immediate class creation) with “lazy” (deferred) strategies, favoring the latter for reduced startup.
Invokedynamic’s dynamic binding enables profile-guided refinements, promising ongoing gains. Brian’s throughput metrics affirm lambdas’ edge, even in capturing scenarios.
Serialization and Bridge Methods
Serializing lambdas invokes writeReplace to a serialized form, preserving semantics without runtime overhead. Brian demos bridge methods for functional interfaces, ensuring compatibility.
Default methods, he notes, extend interfaces safely, avoiding binary breakage—crucial for library evolution.
Lessons from Language Evolution
Brian reflects on Lambda’s odyssey: discarded ideas like inner-class syntactic variants paved the way for invokedynamic’s elegance. This resilience, he posits, exemplifies evolving languages amid obvious-but-flawed intuitions.
Project Lambda’s resources—OpenJDK docs, JCP reviews—invite deeper exploration, with binary builds for experimentation.