This JEP proposes preparing the Java platform for a future where final
truly means final, eliminating the current capability of dynamically modifying final fields via reflection or other privileged code. The goal is to improve performance, security, and maintainability by enabling further runtime optimizations based on the immutability guarantees of final
. This JEP focuses on identifying and mitigating compatibility risks posed by this change, such as existing frameworks and libraries that rely on altering final fields. It outlines an incremental approach involving a new JVM command-line option to enforce final field immutability, allowing developers to test and adapt their code before the restriction becomes the default and eventually permanent. This preparatory work will pave the way for a subsequent JEP to actually finalize the behavior of final
.
BrowserCraft allows you to play a near-complete version of Minecraft Classic (specifically version 0.0.23a_01) directly in your web browser, thanks to the CheerpJ Java to JavaScript/WebAssembly compiler. It requires no installation or plugins, boasting full multiplayer support and even the ability to connect to existing Java Minecraft Classic servers. While aiming for feature parity with the original client, some differences exist, notably enhanced performance in certain areas and potential discrepancies in rendering. The project is open-source and actively being developed, welcoming community contributions.
HN commenters express excitement and curiosity about the technical implementation of a Java Minecraft clone running in the browser. Several discuss the clever use of CheerpJ, a Java-to-WebAssembly compiler, noting its surprisingly good performance and suitability for CPU-bound tasks like Minecraft's game logic. Some commenters raise concerns about performance bottlenecks, particularly related to rendering and garbage collection, while others offer potential optimizations. The project's open-source nature and availability on GitHub are praised, with some expressing interest in contributing. A few commenters reminisce about similar projects in the past, comparing their performance and approaches. The overall sentiment is positive, with the project viewed as an impressive technical feat and a promising demonstration of WebAssembly's capabilities.
This blog post demonstrates how to achieve tail call optimization (TCO) in Java, despite the JVM's lack of native support. The author uses the ASM bytecode manipulation library to transform compiled Java bytecode, replacing recursive tail calls with goto instructions that jump back to the beginning of the method. This avoids stack frame growth and prevents StackOverflowErrors, effectively emulating TCO. The post provides a detailed example, transforming a simple factorial function, and discusses the limitations and potential pitfalls of this approach, including the handling of local variables and debugging challenges. Ultimately, it offers a working, albeit complex, solution for achieving TCO in Java for specific use cases.
Hacker News users generally expressed skepticism about the practicality and value of the approach described in the article. Several commenters pointed out that while technically interesting, using ASM to achieve tail-call optimization in Java is likely to be more trouble than it's worth due to the complexity and potential for subtle bugs. The performance benefits were questioned, with some suggesting that iterative solutions would be simpler and potentially faster. Others noted that relying on such a technique would make code less portable and harder to maintain. A few commenters appreciated the cleverness of the solution, but overall the sentiment leaned towards considering it more of a curiosity than a genuinely useful technique.
JEP 483 introduces a new class loading and linking mechanism called "ahead-of-time" (AOT) loading, aimed at improving startup performance. Unlike the existing dynamic class loading, AOT processes class data during build time, generating a dedicated archive. This archive contains pre-linked classes, readily available at startup, reducing the runtime overhead associated with verification and resolution. While AOT can significantly decrease startup time, particularly for applications with large class hierarchies, it comes with trade-offs. AOT-generated archives increase disk space consumption and require dedicated build-time tooling. Additionally, AOT doesn't replace dynamic class loading entirely; it complements it, handling a predefined set of classes while dynamic loading manages the rest. JEP 483 intends to improve startup, not overall performance, and introduces a new tool called jaotc
to facilitate AOT compilation.
HN commenters generally express interest in JEP 483's potential performance benefits, particularly faster startup times. Some highlight the complexity of the proposed changes and the potential for subtle bugs. A few commenters question the necessity of AOT given existing JIT compiler advancements, while others point out that AOT can offer advantages beyond raw startup speed, such as reduced memory footprint and improved warmup times. One commenter notes the limited scope of the initial JEP, applying only to platform classes, and wonders about future expansion to application classes. Another expresses concern about the potential security implications of pre-compiled code. Several users discuss the interplay between AOT compilation and existing JIT compilation, specifically how the two might be used together effectively.
GhidraMCP is a Ghidra extension that implements a Minecraft Protocol (MCP) server, allowing users to decompile and analyze Minecraft clients while actively interacting with a live game environment. This facilitates dynamic analysis by enabling real-time observation of code execution within Ghidra as the client interacts with the custom server. The project aims to improve the reverse engineering process for Minecraft by providing a controlled and interactive environment for debugging and exploration.
Hacker News users discussed the potential benefits and drawbacks of using GhidraMCP, a collaborative reverse engineering tool. Several commenters praised the project for addressing the need for real-time collaboration in Ghidra, comparing it favorably to existing solutions like Binja's collaborative features. Some expressed excitement about potential workflow improvements, particularly for teams working on the same binary. However, concerns were raised about the security implications of running a server, especially with sensitive data involved in reverse engineering. The practicality of scaling the solution for large binaries and teams was also questioned. While the project generated interest, some users remained skeptical about its performance and long-term viability compared to established collaborative platforms.
The post details the author's successful, albeit challenging, experience installing NetBSD 9.0 on a Sun JavaStation Network Computer (NC). The JavaStation's limited resources and unusual architecture, including its use of a microSPARC IIep processor and a small amount of RAM, presented various hurdles. These included needing to create custom boot floppies and finding compatible network drivers. Despite these difficulties, the author achieved a functional NetBSD installation, showcasing the operating system's portability and the author's persistence. The experience also highlighted the resourcefulness required to repurpose older hardware and the satisfaction of breathing new life into vintage computing platforms.
Commenters on Hacker News largely expressed nostalgia for JavaStations and Sun hardware, reminiscing about their quirks and limitations. Several appreciated the author's dedication to getting NetBSD running on such an unusual and constrained platform. Some discussed the challenges of working with the JavaStation's architecture, including its small amount of RAM and unusual graphics setup. Others shared their own experiences using JavaStations and similar thin clients, with some mentioning their use in educational settings. A few commenters also delved into technical details, discussing the specifics of NetBSD's compatibility and the process of getting X11 functioning.
Chicory is a new WebAssembly runtime built specifically for the Java Virtual Machine (JVM). It aims to bring the performance and portability benefits of Wasm to JVM environments by allowing developers to seamlessly execute Wasm modules directly within their Java applications. Chicory achieves this through a combination of ahead-of-time (AOT) compilation to native code via GraalVM Native Image and a runtime library implemented in Java. This approach allows for efficient interoperability between Java code and Wasm modules, potentially opening up new possibilities for leveraging Wasm's growing ecosystem within established Java systems.
Hacker News users discussed Chicory's potential, limitations, and context within the WebAssembly ecosystem. Some expressed excitement about its JVM integration, seeing it as a valuable tool for leveraging existing Java libraries and infrastructure within WebAssembly applications. Others raised concerns about performance, particularly regarding garbage collection and its suitability for computationally intensive tasks. Comparisons were made to other WebAssembly runtimes like Wasmtime and Wasmer, with discussion around the trade-offs between performance, portability, and features. Several comments questioned the practical benefits of running WebAssembly within the JVM, particularly given the existing rich Java ecosystem. There was also skepticism about WebAssembly's overall adoption and its role in the broader software landscape.
The Minecraft: Legacy Console Edition (LCE), encompassing Xbox 360, PS3, Wii U, and PS Vita versions, has been largely decompiled into human-readable C# code. This project, utilizing a modified version of the UWP disassembler Il2CppInspector, has successfully reconstructed much of the game's functionality, including rendering, world generation, and gameplay logic. While incomplete and not intended for redistribution as a playable game, the decompilation provides valuable insights into the inner workings of these older Minecraft versions and opens up possibilities for modding and preservation efforts.
HN commenters discuss the impressive nature of decompiling a closed-source game like Minecraft: Legacy Console Edition, highlighting the technical skill involved in reversing the obfuscated code. Some express excitement about potential modding opportunities this opens up, like bug fixes, performance enhancements, and restored content. Others raise ethical considerations about the legality and potential misuse of decompiled code, particularly concerning copyright infringement and the creation of unauthorized servers. A few commenters also delve into the technical details of the decompilation process, discussing the tools and techniques used, and speculate about the original development practices based on the decompiled code. Some debate the definition of "decompilation" versus "reimplementation" in this context.
The Elastic blog post details how optimistic concurrency control in Lucene can lead to infrequent but frustrating "document missing" exceptions. These occur when multiple processes try to update the same document simultaneously. Lucene employs versioning to detect these conflicts, preventing data corruption, but the rejected update manifests as the exception. The post outlines strategies for handling this, primarily through retrying the update operation with the latest document version. It further explores techniques for identifying the conflicting processes using debugging tools and log analysis, ultimately aiding in preventing frequent conflicts by optimizing application logic and minimizing the window of contention.
Several commenters on Hacker News discussed the challenges and nuances of optimistic locking, the strategy used by Lucene. One pointed out the inherent trade-off between performance and consistency, noting that optimistic locking prioritizes speed but risks conflicts when multiple writers access the same data. Another commenter suggested using a different concurrency control mechanism like Multi-Version Concurrency Control (MVCC), citing its potential to avoid the update conflicts inherent in optimistic locking. The discussion also touched on the importance of careful implementation, highlighting how overlooking seemingly minor details can lead to difficult-to-debug concurrency issues. A few users shared their personal experiences with debugging similar problems, emphasizing the value of thorough testing and logging. Finally, the complexity of Lucene's internals was acknowledged, with one commenter expressing surprise at the described issue existing within such a mature project.
After a year of using Go professionally, the author reflects positively on the switch from Java. Go's simplicity, speed, and built-in concurrency features significantly boosted productivity. While missing Java's mature ecosystem and advanced tooling, particularly IntelliJ IDEA, the author found Go's lightweight tools sufficient and appreciated the language's straightforward error handling and fast compilation times. The learning curve was minimal, and the overall experience improved developer satisfaction and project efficiency, making the transition worthwhile.
Many commenters on Hacker News appreciated the author's honest and nuanced comparison of Java and Go. Several highlighted the cultural differences between the ecosystems, noting Java's enterprise focus and Go's emphasis on simplicity. Some questioned the author's assessment of Go's error handling, arguing that it can be verbose, though others defended it as explicit and helpful. Performance benefits of Go were acknowledged but some suggested they might be overstated for typical applications. A few Java developers shared their positive experiences with newer Java features and frameworks, contrasting the author's potentially outdated perspective. Several commenters also mentioned the importance of choosing the right tool for the job, recognizing that neither language is universally superior.
iText, a popular Java PDF library, is celebrating its 25th anniversary with the release of iText Suite 9.1. This release focuses on improved SVG and CSS support, enabling developers to more easily incorporate these web technologies into PDF documents. Performance enhancements, particularly for table rendering, are also a key feature of this update. Additionally, iText DITO, the low-code PDF template generator, now offers a JavaScript API and several other improvements. The post emphasizes iText's long history and commitment to providing powerful PDF manipulation tools for developers.
Hacker News users discussed iText's longevity and evolution. Some expressed frustration with its licensing changes over the years, transitioning from AGPL to a commercial model. Others praised its performance improvements, particularly with SVG and CSS handling in the latest version. Several commenters shared their experiences using iText, highlighting its utility for generating complex PDFs, while acknowledging the learning curve involved. The licensing changes prompted a discussion about open-source alternatives, with Apache PDFBox frequently mentioned. Some users also pointed out quirks and limitations they encountered, such as font handling and table creation complexities.
Robocode is a programming game where you code robot tanks in Java or .NET to battle against each other in a real-time arena. Robots are programmed with artificial intelligence to strategize, move, target, and fire upon opponents. The platform provides a complete development environment with a custom robot editor, compiler, debugger, and battle simulator. Robocode is designed to be educational and entertaining, allowing programmers of all skill levels to improve their coding abilities while enjoying competitive robot combat. It's free and open-source, offering a simple API and a wealth of documentation to help get started.
HN users fondly recall Robocode as a fun and educational tool for learning Java, programming concepts, and even AI basics. Several commenters share nostalgic stories of playing it in school or using it for programming competitions. Some lament its age and lack of modern features, suggesting updates like better graphics or web integration could revitalize it. Others highlight the continuing relevance of its core mechanics and the existence of active communities still engaging with Robocode. The educational value is consistently praised, with many suggesting its potential for teaching children programming in an engaging way. There's also discussion of alternative robot combat simulators and the challenges of updating older Java codebases.
Faced with the unsustainable maintenance burden of his popular open-source Java linear algebra library, ND4J, the author founded Timefold.ai. The library's widespread use in commercial settings, coupled with the limited resources available for its upkeep through traditional open-source avenues like donations and sponsorships, led to this decision. Timefold offers commercial support and enterprise features built upon ND4J, generating revenue that directly funds the continued development and maintenance of the open-source project. This model allows the library to thrive and remain freely available, while simultaneously providing a sustainable business model based on its value.
Hacker News users generally praised the Timefold founder's ingenuity and resourcefulness in creating a business around his open-source project. Several commenters discussed the challenges of monetizing open-source software, with some suggesting alternative models like donations or dual licensing. A few expressed skepticism about the long-term viability of relying on commercializing closed-source extensions, particularly given the rapid advancements in open-source LLMs. Some users also debated the ethics of restricting certain features to paying customers, while others emphasized the importance of sustainable funding for open-source projects. The founder's transparency and clear explanation of his motivations were widely appreciated.
OpenLDK is a project that implements a Java Virtual Machine (JVM) and Just-In-Time (JIT) compiler written entirely in Common Lisp. It aims to be a high-performance JVM alternative, leveraging Lisp's metaprogramming capabilities for dynamic code generation and optimization. The project features a modular design, encompassing a bytecode interpreter, a tiered JIT compiler using a method-based compilation strategy, and a garbage collector. OpenLDK is considered experimental and under active development, focusing on performance enhancements and broader Java compatibility.
Commenters on Hacker News express interest in OpenLDK, primarily focusing on its unusual implementation of a Java Virtual Machine (JVM) in Common Lisp. Several question the practical applications and performance implications of this approach, wondering about its speed and suitability for real-world projects. Some highlight the potential benefits of Lisp's dynamic nature for tasks like debugging and introspection. Others draw parallels to similar projects like Clojure and GraalVM, discussing their respective advantages and disadvantages. A few express skepticism about the long-term viability of the project, while others praise the technical achievement and express curiosity about its potential. The novelty of using Lisp for JVM implementation clearly sparks the most discussion.
Groundhog AI has launched a Spring Boot API that allows developers to easily integrate "groundhog day" loops into their applications. This API enables the creation of repeatable scenarios where code execution can be rewound and replayed, facilitating debugging, testing, and the development of AI agents that learn through trial and error within controlled environments. The API offers endpoints for starting, stopping, and stepping through loops, as well as for retrieving and setting loop variables. It's designed to be simple to use and integrate with existing Java projects, providing a new tool for developers working with complex systems or iterative learning processes.
HN users discussed the novelty and potential usefulness of the Groundhog Day API. Some questioned its practical applications beyond the initial amusement, while others saw potential for testing and debugging time-dependent systems. Several commenters pointed out the inherent limitations and potential inaccuracies of weather data, especially historical data. The simplistic nature of the API was both praised for its ease of use and criticized for its lack of advanced features. Some suggested potential improvements, like incorporating other data sources from the movie or expanding to include other cyclical events. A few expressed concern about potential copyright issues.
The blog post analyzes Caffeine, a Java caching library, focusing on its performance characteristics. It delves into Caffeine's core data structures, explaining how it leverages a modified version of the W-TinyLFU admission policy to effectively manage cached entries. The post examines the implementation details of this policy, including how it tracks frequency and recency of access through a probabilistic counting structure called the Sketch. It also explores Caffeine's use of a segmented, concurrent hash table, highlighting its role in achieving high throughput and scalability. Finally, the post discusses Caffeine's eviction process, demonstrating how it utilizes the TinyLFU policy and window-based sampling to maintain an efficient cache.
Hacker News users discussed Caffeine's design choices and performance characteristics. Several commenters praised the library's efficiency and clever implementation of various caching strategies. There was particular interest in its use of Window TinyLFU, a sophisticated eviction policy, and how it balances hit rate with memory usage. Some users shared their own experiences using Caffeine, highlighting its ease of integration and positive impact on application performance. The discussion also touched upon alternative caching libraries like Guava Cache and the challenges of benchmarking caching effectively. A few commenters delved into specific code details, discussing the use of generics and the complexity of concurrent data structures.
JReleaser simplifies and automates project releases across various platforms. It streamlines the process of creating release artifacts, generating checksums, and publishing them to a variety of distribution channels, including package managers like Homebrew, SDKMAN!, and Chocolatey, as well as artifact repositories like Maven Central, and GitHub Releases. JReleaser supports multiple project types (Java, Go, Kotlin, etc.) and offers flexible configuration through its declarative approach, allowing developers to define release logic in a centralized manner and avoid tedious manual steps. This frees up developers to focus on coding rather than deployment logistics.
Hacker News users generally reacted positively to JReleaser, praising its simplicity and ease of use compared to more complex tools. Several commenters appreciated its support for various platforms and package managers, finding it particularly useful for Java projects but also applicable to other languages. Some pointed out potential alternatives like goreleaser, while others discussed the benefits of standardizing release processes. A few users inquired about specific features, such as signing and checksum generation, while others shared their personal experiences using JReleaser for their own projects. The overall sentiment leaned towards JReleaser being a valuable tool for streamlining and automating the release process.
Tabby is a self-hosted AI coding assistant designed to enhance programming productivity. It offers code completion, generation, translation, explanation, and chat functionality, all within a secure local environment. By leveraging large language models like StarCoder and CodeLlama, Tabby provides powerful assistance without sharing code with external servers. It's designed to be easily installed and customized, offering both a desktop application and a VS Code extension. The project aims to be a flexible and private alternative to cloud-based AI coding tools.
Hacker News users discussed Tabby's potential, limitations, and privacy implications. Some praised its self-hostable nature as a key advantage over cloud-based alternatives like GitHub Copilot, emphasizing data security and cost savings. Others questioned its offline performance compared to online models and expressed skepticism about its ability to truly compete with more established tools. The practicality of self-hosting a large language model (LLM) for individual use was also debated, with some highlighting the resource requirements. Several commenters showed interest in using Tabby for exploring and learning about LLMs, while others were more focused on its potential as a practical coding assistant. Concerns about the computational costs and complexity of setup were common threads. There was also some discussion comparing Tabby to similar projects.
Summary of Comments ( 112 )
https://news.ycombinator.com/item?id=43538919
HN commenters largely discuss the implications of making
final
mean truly final in Java. Some express concern about the performance impact, particularly for JIT compilers and escape analysis. Others question the practicality and benefit, given the existing workarounds likesealed
classes and the potential disruption to existing codebases. A few commenters welcome the change, seeing it as a positive step toward stricter immutability and potentially simplifying some aspects of the language. There's also discussion around the nuances of the proposal, such as its impact on method overriding and the interaction with reflection. Several users highlight the complexity of implementing this change in the JVM and the potential for unforeseen consequences.The Hacker News post titled "JEP draft: Prepare to make final mean final" (https://news.ycombinator.com/item?id=43538919) discussing the JEP draft at https://openjdk.org/jeps/8349536, has a moderate number of comments, exploring different facets of the proposed change.
Several commenters discuss the implications for mocking frameworks like Mockito. One user points out the potential difficulties this change poses for testing and mocking, as overriding final methods is a common technique employed by these frameworks. They question the practicality of the proposed solution of using method handles for mocking, expressing concern about the performance overhead and complexity it might introduce. Another user suggests that this change might push developers towards compile-time mocking solutions or different testing strategies altogether. The discussion around Mockito highlights a significant trade-off between stricter language semantics and the flexibility required for testing.
The performance implications of the JEP are also a topic of discussion. One commenter questions whether the potential performance gains from this change are significant enough to justify the disruption it would cause to existing codebases and testing practices. Another user counters this by arguing that while the immediate performance gains might be minimal, it lays the groundwork for future optimizations by the JVM, enabling more aggressive inlining and other optimizations based on the guarantee of finality.
Another thread of discussion revolves around the meaning of "final" in other languages and contexts. A commenter draws parallels to C++, noting the different meanings of "const" in different contexts and expressing a preference for Java's clearer distinction between final fields and final methods. This comparison highlights the nuances of the concept of "finality" in object-oriented programming.
One user brings up the issue of inner classes accessing fields of the enclosing class, a situation where the effective finality of fields is important for performance but not explicitly enforced by the
final
keyword. They suggest that the JEP could clarify the treatment of such effectively final fields.Some users express general support for the JEP, viewing it as a step towards cleaner and more predictable code. They argue that the current behavior of "final" can be confusing and that enforcing its intended meaning would lead to more robust and maintainable programs.
Finally, there's a short discussion about the practicality of migrating existing codebases to comply with this change. One commenter suggests that automated tooling could help with the transition, mitigating the potential disruption.
Overall, the comments reflect a mixed reception to the proposed JEP. While some appreciate the stricter semantics and potential performance benefits, others express concerns about the impact on testing practices and the effort required for migration. The discussion highlights the complex trade-offs involved in evolving a mature language like Java.