Posts Tagged ‘DevoxxBE2012’
[DevoxxBE2012] On the Road to JDK 8: Lambda, Parallel Libraries, and More
Joseph Darcy, a key figure in Oracle’s JDK engineering team, presented an insightful overview of JDK 8 developments. With extensive experience in language evolution, including leading Project Coin for JDK 7, Joseph outlined the platform’s future directions, balancing innovation with compatibility.
He began by contextualizing JDK 8’s major features, particularly lambda expressions and default methods, set for release in September 2013. Joseph polled the audience on JDK usage, noting the impending end of public updates for JDK 6 and urging transitions to newer versions.
Emphasizing a quantitative approach to compatibility, Joseph described experiments analyzing millions of lines of code to inform decisions, such as lambda conversions from inner classes.
Evolving the Language with Compatibility in Mind
Joseph elaborated on the JDK’s evolution policy, prioritizing binary compatibility while allowing measured source and behavioral changes. He illustrated this with diagrams showing compatibility spaces for different release types, from updates to full platforms.
A core challenge, he explained, is evolving interfaces compatibly. Unlike classes, interfaces cannot add methods without breaking implementations. To address this, JDK 8 introduces default methods, enabling API evolution without user burden.
This ties into lambda support, where functional interfaces facilitate closures. Joseph contrasted this with past changes like generics, which preserved migration compatibility through erasure, avoiding VM modifications.
Lambda Expressions and Implementation Techniques
Diving into lambdas, Joseph defined them as anonymous methods capturing enclosing scope values. He traced their long journey into Java, noting their ubiquity in modern languages.
For implementation, Joseph rejected simple inner class translations due to class explosion and performance overhead. Instead, JDK 8 leverages invokedynamic from JDK 7, allowing runtime strategies like class spinning or method handles.
This indirection decouples binary representation from implementation, enabling optimizations. Joseph shared benchmarks showing non-capturing lambdas outperforming inner classes, especially multithreaded.
Serialization posed challenges, resolved via indirection to reconstruct lambdas independently of runtime details.
Parallel Libraries and Bulk Operations
Joseph highlighted how lambdas enable powerful libraries, abstracting behavior as generics abstract types. Streams introduce pipeline operations—filter, map, reduce—with laziness and fork-join parallelism.
Using the Fork/Join Framework from JDK 7, these libraries handle load balancing implicitly, encapsulating complexity. Joseph demonstrated conversions from collections to streams, facilitating scalable concurrent applications.
Broader JDK 8 Features and Future Considerations
Beyond lambdas, Joseph mentioned annotations on types and repeating annotations, enhancing expressiveness. He stressed deferring decisions to avoid constraining future evolutions, like potential method reference enhancements.
In summary, Joseph portrayed JDK 8 as a coordinated update across language, libraries, and VM, inviting community evaluation through available builds.
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[DevoxxBE2012] Spring 3.2 and 3.2 Themes and Trends
In a dynamic presentation, Josh Long, a prominent Spring developer advocate and author, delved into the evolving landscape of the Spring Framework. As someone deeply embedded in the Spring ecosystem, Josh highlighted how Spring continues to address modern development challenges while maintaining its core principles. He began by recapping the framework’s foundational aspects, emphasizing its role in promoting clean, extensible code without unnecessary reinvention.
Josh explained that Spring operates as a lightweight dependency injection container, layered with vertical technologies for diverse needs like mobile development, big data handling, and web applications. This decoupling from underlying infrastructure enables seamless transitions between environments, from traditional servers to cloud platforms. He noted the increasing complexity in data stores, caching solutions, and client interfaces, underscoring Spring’s relevance in today’s fragmented tech world. By focusing on dependency injection, aspect-oriented programming, and portable service abstractions, Spring empowers developers to build robust, maintainable systems.
Transitioning to recent advancements, Josh reviewed Spring 3.1, released in December 2011, which introduced features like environment profiles and Java-based configuration. These enhancements facilitate tailored bean activations across development stages, simplifying configurations that diverge between local setups and production clouds. He illustrated this with examples of data sources, showing how profiles partition configurations effectively.
Moreover, Josh discussed the caching abstraction in Spring 3.1, which provides a unified SPI for various caches like EHCache and Redis. This abstraction, combined with annotations for cache management, streamlines performance optimizations without locking developers into specific implementations.
Core Refinements in Spring 3.2
Shifting focus to Spring 3.2, slated for release by year’s end, Josh outlined its core refinements. Building on Java 7, it incorporates asynchronous support from Servlet 3.0, enabling efficient handling of long-running tasks in web applications. He demonstrated this with controller methods returning Callable or DeferredResult, allowing requests and responses to process in separate threads, enhancing scalability.
Josh also introduced the Spring MVC Test Framework, a tool for unit testing controllers with mocked servlet APIs. This framework, revamped for 3.2, integrates seamlessly with existing test contexts, promoting better code quality through isolated testing.
Additionally, upgrades to the Spring Expression Language (SpEL) and backported features from 3.1.x bolster the framework’s expressiveness and compatibility. Josh emphasized that these changes maintain Spring’s low-risk upgrade path, ensuring stability for enterprise adopters.
Looking Ahead to Spring 3.3
Josh then previewed Spring 3.3, expected in late 2013, which promises substantial innovations. Central to this release is support for Java SE 8 features, including lambdas, which align naturally with Spring’s single abstract method interfaces. He showcased how lambdas simplify callbacks in components like JdbcTemplate, reducing boilerplate code.
Furthermore, Josh touched on enhanced Groovy support and the integration of the Grails Bean Builder, expanding Spring’s appeal for dynamic languages. The release will also track Java EE 7 APIs, such as JCache 1.0 and JMS 2.0, with annotation-centric endpoints for message-driven architectures.
WebSocket support, crucial for real-time web applications, will be fully integrated into Spring MVC, complementing existing messaging capabilities in Spring Integration.
Strategic Motivations and Community Impact
Throughout his talk, Josh articulated the motivations behind Spring’s shorter release cycles, aiming to deliver timely features without overwhelming users. He stressed the framework’s alignment with emerging standards, positioning it as a bridge between Java SE 7/8 and EE 7.
Josh also shared insights into community contributions, mentioning the GitHub-based model and Gradle builds that foster collaboration. He encouraged feedback, highlighting his role in curating community resources like the weekly roundup on springsource.org.
In closing, Josh fielded questions on topics like bean metadata navigation and conditional caching, reinforcing Spring’s commitment to developer productivity. His enthusiasm underscored Spring’s enduring value in navigating the complexities of modern software engineering.