DOCSLIB.ORG

Maxine-VM Documentation Release 2.9.0

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Maxine-VM Documentation Release 2.9.0 Maxine-VM Documentation Release 2.9.0 The Maxine Team of the University of Manchester Jun 18, 2020 Contents 1 Project Overview3 2 Citation 5 3 Getting Started7 4 Features 9 5 Roadmap 11 6 Acknowledgements 13 7 Table of Contents 15 7.1 Build and Usage Instructions................................ 15 7.2 Status............................................ 19 7.3 Developing Maxine on IDEs................................ 22 7.4 Papers and Presentations.................................. 25 7.5 The Maxine Project: Contributors............................. 29 7.6 Debugging......................................... 32 7.7 Offline Compilation.................................... 35 7.8 Frequently Asked Questions................................ 40 7.9 Glossary of Maxine terminology and concepts...................... 42 7.10 Actors........................................... 47 7.11 JDK interoperation..................................... 49 7.12 VM Boot Image...................................... 53 7.13 Memory Management................................... 60 7.14 Management of Code Dependencies............................ 61 7.15 Code Eviction in the Maxine VM............................. 63 7.16 Object representation in the Maxine VM......................... 65 7.17 Schemes: Interfaces for Maxine VM Configuration.................... 73 7.18 Snippets in the Maxine VM................................ 77 7.19 Stack Walking in the Maxine VM............................. 84 7.20 Threads in the Maxine VM................................. 88 7.21 Type-based Logging.................................... 94 7.22 Virtual Machine Level Analysis.............................. 99 7.23 VM Operations....................................... 113 7.24 VM Tooling interface................................... 117 i 7.25 The Maxine Inspector................................... 119 8 Indices and tables 179 ii Maxine-VM Documentation, Release 2.9.0 A next generation, highly productive platform for virtual machine research. Contents 1 Maxine-VM Documentation, Release 2.9.0 2 Contents CHAPTER 1 Project Overview In this era of modern, managed languages we demand ever more from our virtual machines: better performance, more scalability, and support for the latest new languages. Research and experimentation is essential but challenging in the context of mature, complex, production VMs written in multiple languages. The Maxine VM is a next generation platform that establishes a new standard of productivity in this area of research. It is written entirely in Java, completely compatible with modern Java IDEs and the standard JDK, features a modular architecture that permits alternate implementations of subsystems such as GC and compilation to be plugged in, and is accompanied by a dedicated development tool (the Maxine Inspector) for debugging and visualizing nearly every aspect of the VM’s runtime state. As of the 2.0 release, September 2013, Maxine is no longer an active project at Oracle Labs. As of the 2.1 release, April 2017, Maxine VM is actively maintained and developed at the University of Manchester. We believe that Maxine represents the state of the art in a research VM, and actively encourage community involvement. The Maxine sources, including VM, Inspector, and other supporting tools, are Open Source and are licensed under GPL version 2.0. To obtain the code please visit https: //github.com/beehive-lab. 3 Maxine-VM Documentation, Release 2.9.0 4 Chapter 1. Project Overview CHAPTER 2 Citation For Maxine VM >= v2.1 please cite: Christos Kotselidis, et al. Heterogeneous Managed Runtime Sys- tems: A Computer Vision Case Study. In 13th ACM SIGPLAN/SIGOPS International Conference on Virtual Execution Environments (VEE), 2017. For the original Maxine VM please cite: C. Wimmer et al, “Maxine: An approachable virtual machine for, and in, java”, In ACM TACO 2013. To cite the software itself please use. 5 Maxine-VM Documentation, Release 2.9.0 6 Chapter 2. Citation CHAPTER 3 Getting Started • Download and build Maxine from source on any of the supported Supported Platforms. • Read the technical report “Maxine: An Approachable Virtual Machine For, and In, Java” • Send any questions to this mailing list([email protected]). • Read about the current status of the VM. • Learn more about the Maxine Inspector, the companion tool for visualizing internal state and debugging the VM: video introduction, video demos, and written documentation. • Learn more about Virtual Machine Level Analysis, an experimental extension for analysis the behavior of application (and eventually the VM). • View publications and presentations about Maxine. • Read the Glossary and FAQ. • Contact us on the the mailing list (or in private) and tell us about your work. 7 Maxine-VM Documentation, Release 2.9.0 8 Chapter 3. Getting Started CHAPTER 4 Features Some of the features of Maxine that make it a compelling platform for (J)VM research include: • Nearly all of the code base is written in Java and exploits advanced language features appearing in JDK 5 and beyond: for example annotations, static imports, and generics. • The VM integrates with openJDK. There’s no need to download (and build) other implementations of the standard Java classes. • The source code supports development in Eclipse, Netbeans or IntelliJ all of which provide ex- cellent support for cross-referencing and browsing the code. It also means that refactoring can be confidently employed to continuously improve the structure of the code. • The Maxine Inspector produces visualizations of nearly every aspect of the VM runtime state, and provides advanced, VM-specific debugging. • The source code is hosted on GitHub making downloading and collaboration easier. 9 Maxine-VM Documentation, Release 2.9.0 10 Chapter 4. Features CHAPTER 5 Roadmap • Implement JVMCI, Upgrade to latest Graal • Run Truffle on top of Maxine VM/Graal • Port MMTk to Maxine VM 11 Maxine-VM Documentation, Release 2.9.0 12 Chapter 5. Roadmap CHAPTER 6 Acknowledgements This documentation is heavily based on the original wiki pages (by Oracle) that can be found here and here. 13 Maxine-VM Documentation, Release 2.9.0 14 Chapter 6. Acknowledgements CHAPTER 7 Table of Contents 7.1 Build and Usage Instructions The easiest way to build and use Maxine is through the beehivelab/maxine-dev docker image. This image comes with all dependencies installed and configured. You only need to get the latest maxine sources and build them through the container. Note: If for some reason using docker is not desirable/possible please refer to the end of this page for instructions on building maxine without docker. 7.1.1 Getting the source code The docker image expects the source code to be in the layout shown below: $ tree -L1 maxine-src maxine-src maxine mx To get the source code in this layout execute: $ mkdir maxine-src $ git clone https://github.com/graalvm/mx.git maxine-src/mx $ git clone https://github.com/beehive-lab/Maxine-VM.git maxine-src/maxine 7.1.2 Developing using a docker container On macOS (and Windows) unfortunately simply mounting host directories on docker containers, al- though functional, is slow. To work arround this issue we use docker-sync. Additionally we run an rsync daemon on the docker container, this way users that don’t want to use docker-sync can manualy 15 Maxine-VM Documentation, Release 2.9.0 rsync files from the host to the container and vice versa (through rsync://localhost:9873/ root which maps to /root/ on the container). To create a docker container named maxine-dev from the beehivelab/maxine-dev docker image enter maxine-src/maxine/docker and run: docker-compose up --no-start Note that the container is now created but does not contain the source code. Keeping your data on the host in sync with your data on the docker container Install docker-rsync: gem install docker-sync To start it enter maxine-src/maxine/docker/ and run: docker-sync start To stop it: docker-sync stop Using the maxine-dev container To use the container issue docker start -i maxine-dev. This will start the container and open a bash shell in it. From this shell you can build and run maxine. As long as docker-sync is running any changes you make on the host or the container will become visible to the counterpart as well. To exit the shell and stop the container type Ctrl-D. 7.1.3 Build • Enter the maxine source directory: cd $MAXINE_HOME • Compile the source code: mx build Executing mx build in the $MAXINE_HOME directory compiles the Java source code of Maxine to class files using javac (or the Eclipse batch compiler if you use the -jdt option) and compiles the native code of Maxine to executable code using your platform’s C compiler. The build process attempts to download some necessary files from the internet. If you are behind a firewall set the HTTP_PROXY environment variable appropriately before starting the build. • Generate the boot image: mx image 16 Chapter 7. Table of Contents Maxine-VM Documentation, Release 2.9.0 The mx image command is used to generate a boot image. This command runs Maxine on a host JVM to configure a prototype, then compiles its own code and data to create an executable program for the target platform. 7.1.4 Running With the native substrate and a boot image built, the Maxine VM can now be executed. The mx vm command handles the details of class and library paths and provides an interface similar to the standard java launcher command. The mx script includes a command to run a simple HelloWorld program to verify that the VM is working: mx helloworld Now let’s use Maxine to run a more substantial program: mx vm -cp test/bin test.output.GCTest2 To launch the VM (or any other command for that matter) without using mx, the -v option echoes the commands issued by the mx script: mx -v helloworld 7.1.5 Creating a Maxine-based JDK To create a Maxine-based JDK that can serve as a replacement for OpenJDK or OracleJDK issue: mx makejdk This will create the directory $MAXINE_HOME/maxjdk which you can now use as the JAVA_HOME for running java with Maxine. 7.1.6 Profiling Various profiling tools are available for the Java platform, with varying degrees of overhead.
Load more

Recommended publications
  • Building Openjfx
    Building OpenJFX Building a UI toolkit for many different platforms is a complex and challenging endeavor. It requires platform specific tools such as C compilers as well as portable tools like Gradle and the JDK. Which tools must be installed differs from platform to platform. While the OpenJFX build system was designed to remove as many build hurdles as possible, it is necessary to build native code and have the requisite compilers and toolchains installed. On Mac and Linux this is fairly easy, but setting up Windows is more difficult. If you are looking for instructions to build FX for JDK 8uNNN, they have been archived here. Before you start Platform Prerequisites Windows Missing paths issue Mac Linux Ubuntu 18.04 Ubuntu 20.04 Oracle Enterprise Linux 7 and Fedora 21 CentOS 8 Common Prerequisites OpenJDK Git Gradle Ant Environment Variables Getting the Sources Using Gradle on The Command Line Build and Test Platform Builds NOTE: cross-build support is currently untested in the mainline jfx-dev/rt repo Customizing the Build Testing Running system tests with Robot Testing with JDK 9 or JDK 10 Integration with OpenJDK Understanding a JDK Modular world in our developer build Adding new packages in a modular world First Step - development Second Step - cleanup Before you start Do you really want to build OpenJFX? We would like you to, but the latest stable build is already available on the JavaFX website, and JavaFX 8 is bundled by default in Oracle JDK 8 (9 and 10 also included JavaFX, but were superseded by 11, which does not).
    [Show full text]
  • Toward Harnessing High-Level Language Virtual Machines for Further Speeding up Weak Mutation Testing
    2012 IEEE Fifth International Conference on Software Testing, Verification and Validation Toward Harnessing High-level Language Virtual Machines for Further Speeding up Weak Mutation Testing Vinicius H. S. Durelli Jeff Offutt Marcio E. Delamaro Computer Systems Department Software Engineering Computer Systems Department Universidade de Sao˜ Paulo George Mason University Universidade de Sao˜ Paulo Sao˜ Carlos, SP, Brazil Fairfax, VA, USA Sao˜ Carlos, SP, Brazil [email protected] [email protected] [email protected] Abstract—High-level language virtual machines (HLL VMs) have tried to exploit the control that HLL VMs exert over run- are now widely used to implement high-level programming ning programs to facilitate and speedup software engineering languages. To a certain extent, their widespread adoption is due activities. Thus, this research suggests that software testing to the software engineering benefits provided by these managed execution environments, for example, garbage collection (GC) activities can benefit from HLL VMs support. and cross-platform portability. Although HLL VMs are widely Test tools are usually built on top of HLL VMs. However, used, most research has concentrated on high-end optimizations they often end up tampering with the emergent computation. such as dynamic compilation and advanced GC techniques. Few Using features within the HLL VMs can avoid such problems. efforts have focused on introducing features that automate or fa- Moreover, embedding testing tools within HLL VMs can cilitate certain software engineering activities, including software testing. This paper suggests that HLL VMs provide a reasonable significantly speedup computationally expensive techniques basis for building an integrated software testing environment. As such as mutation testing [6].
    [Show full text]
  • Bypassing Portability Pitfalls of High-Level Low-Level Programming
    Bypassing Portability Pitfalls of High-level Low-level Programming Yi Lin, Stephen M. Blackburn Australian National University [email protected], [email protected] Abstract memory-safety, encapsulation, and strong abstraction over hard- Program portability is an important software engineering consider- ware [12], which are desirable goals for system programming as ation. However, when high-level languages are extended to effec- well. Thus, high-level languages are potential candidates for sys- tively implement system projects for software engineering gain and tem programming. safety, portability is compromised—high-level code for low-level Prior research has focused on the feasibility and performance of programming cannot execute on a stock runtime, and, conversely, applying high-level languages to system programming [1, 7, 10, a runtime with special support implemented will not be portable 15, 16, 21, 22, 26–28]. The results showed that, with proper ex- across different platforms. tension and restriction, high-level languages are able to undertake We explore the portability pitfall of high-level low-level pro- the task of low-level programming, while preserving type-safety, gramming in the context of virtual machine implementation tasks. memory-safety, encapsulation and abstraction. Notwithstanding the Our approach is designing a restricted high-level language called cost for dynamic compilation and garbage collection, the perfor- RJava, with a flexible restriction model and effective low-level ex- mance of high-level languages when used to implement a virtual tensions, which is suitable for different scopes of virtual machine machine is still competitive with using a low-level language [2]. implementation, and also suitable for a low-level language bypass Using high-level languages to architect large systems is bene- for improved portability.
    [Show full text]
  • Here I Led Subcommittee Reports Related to Data-Intensive Science and Post-Moore Computing) and in CRA’S Board of Directors Since 2015
    Vivek Sarkar Curriculum Vitae Contents 1 Summary 2 2 Education 3 3 Professional Experience 3 3.1 2017-present: College of Computing, Georgia Institute of Technology . 3 3.2 2007-present: Department of Computer Science, Rice University . 5 3.3 1987-2007: International Business Machines Corporation . 7 4 Professional Awards 11 5 Research Awards 12 6 Industry Gifts 15 7 Graduate Student and Other Mentoring 17 8 Professional Service 19 8.1 Conference Committees . 20 8.2 Advisory/Award/Review/Steering Committees . 25 9 Keynote Talks, Invited Talks, Panels (Selected) 27 10 Teaching 33 11 Publications 37 11.1 Refereed Conference and Journal Publications . 37 11.2 Refereed Workshop Publications . 51 11.3 Books, Book Chapters, and Edited Volumes . 58 12 Patents 58 13 Software Artifacts (Selected) 59 14 Personal Information 60 Page 1 of 60 01/06/2020 1 Summary Over thirty years of sustained contributions to programming models, compilers and runtime systems for high performance computing, which include: 1) Leading the development of ASTI during 1991{1996, IBM's first product compiler component for optimizing locality, parallelism, and the (then) new FORTRAN 90 high-productivity array language (ASTI has continued to ship as part of IBM's XL Fortran product compilers since 1996, and was also used as the foundation for IBM's High Performance Fortran compiler product); 2) Leading the research and development of the open source Jikes Research Virtual Machine at IBM during 1998{2001, a first-of-a-kind Java Virtual Machine (JVM) and dynamic compiler implemented
    [Show full text]
  • Techniques for Real-System Characterization of Java Virtual Machine Energy and Power Behavior Gilberto Contreras Margaret Martonosi
    Techniques for Real-System Characterization of Java Virtual Machine Energy and Power Behavior Gilberto Contreras Margaret Martonosi Department of Electrical Engineering Princeton University 1 Why Study Power in Java Systems? The Java platform has been adopted in a wide variety of devices Java servers demand performance, embedded devices require low-power Performance is important, power/energy/thermal issues are equally important How do we study and characterize these requirements in a multi-layer platform? 2 Power/Performance Design Issues Java Application Java Virtual Machine Operating System Hardware 3 Power/Performance Design Issues Java Application Garbage Class Runtime Execution Collection LoaderJava VirtualCompiler MachineEngine Operating System Hardware How do the various software layers affect power/performance characteristics of hardware? Where should time be invested when designing power and/or thermally aware Java virtual Machines? 4 Outline Approaches for Energy/Performance Characterization of Java virtual machines Methodology Breaking the JVM into sub-components Hardware-based power/performance characterization of JVM sub-components Results Jikes & Kaffe on Pentium M Kaffe on Intel XScale Conclusions 5 Power & Performance Analysis of Java Simulation Approach √ Flexible: easy to model non-existent hardware x Simulators may lack comprehensiveness and accuracy x Thermal studies require tens of seconds granularity Accurate simulators are too slow Hardware Approach √ Able to capture full-system characteristics
    [Show full text]
  • Java Version 40 Download Apache Tomcat ® Welcome to the Apache Tomcat ® 9.X Software Download Page
    java version 40 download Apache Tomcat ® Welcome to the Apache Tomcat ® 9.x software download page. This page provides download links for obtaining the latest version of Tomcat 9.0.x software, as well as links to the archives of older releases. Unsure which version you need? Specification versions implemented, minimum Java version required and lots more useful information may be found on the 'which version?' page. Quick Navigation. Release Integrity. You must verify the integrity of the downloaded files. We provide OpenPGP signatures for every release file. This signature should be matched against the KEYS file which contains the OpenPGP keys of Tomcat's Release Managers. We also provide SHA-512 checksums for every release file. After you download the file, you should calculate a checksum for your download, and make sure it is the same as ours. Mirrors. You are currently using https://mirror.softaculous.com/apache/ . If you encounter a problem with this mirror, please select another mirror. If all mirrors are failing, there are backup mirrors (at the end of the mirrors list) that should be available. Please see the README file for packaging information. It explains what every distribution contains. Apache Tomcat ® The Apache Tomcat ® software is an open source implementation of the Jakarta Servlet, Jakarta Server Pages, Jakarta Expression Language, Jakarta WebSocket, Jakarta Annotations and Jakarta Authentication specifications. These specifications are part of the Jakarta EE platform. The Jakarta EE platform is the evolution of the Java EE platform. Tomcat 10 and later implement specifications developed as part of Jakarta EE. Tomcat 9 and earlier implement specifications developed as part of Java EE.
    [Show full text]
  • Apache Harmony Project Tim Ellison Geir Magnusson Jr
    The Apache Harmony Project Tim Ellison Geir Magnusson Jr. Apache Harmony Project http://harmony.apache.org TS-7820 2007 JavaOneSM Conference | Session TS-7820 | Goal of This Talk In the next 45 minutes you will... Learn about the motivations, current status, and future plans of the Apache Harmony project 2007 JavaOneSM Conference | Session TS-7820 | 2 Agenda Project History Development Model Modularity VM Interface How Are We Doing? Relevance in the Age of OpenJDK Summary 2007 JavaOneSM Conference | Session TS-7820 | 3 Agenda Project History Development Model Modularity VM Interface How Are We Doing? Relevance in the Age of OpenJDK Summary 2007 JavaOneSM Conference | Session TS-7820 | 4 Apache Harmony In the Beginning May 2005—founded in the Apache Incubator Primary Goals 1. Compatible, independent implementation of Java™ Platform, Standard Edition (Java SE platform) under the Apache License 2. Community-developed, modular architecture allowing sharing and independent innovation 3. Protect IP rights of ecosystem 2007 JavaOneSM Conference | Session TS-7820 | 5 Apache Harmony Early history: 2005 Broad community discussion • Technical issues • Legal and IP issues • Project governance issues Goal: Consolidation and Consensus 2007 JavaOneSM Conference | Session TS-7820 | 6 Early History Early history: 2005/2006 Initial Code Contributions • Three Virtual machines ● JCHEVM, BootVM, DRLVM • Class Libraries ● Core classes, VM interface, test cases ● Security, beans, regex, Swing, AWT ● RMI and math 2007 JavaOneSM Conference | Session TS-7820 |
    [Show full text]
  • Oracle to Openjdk Migrations
    DATASHEET Make the Move from Oracle Java to Supported OpenJDK Oracle License Changes Cost of Cost of Number Number Oracle Java OpenJDK OpenLogic of Core of The new licensing requirements for Oracle Java SE Annual Annual Support Users Servers SE subscriptions have prompted many appli- Subscription Subscription cation development teams to reevaluate their 512 32 $92,160 $0 $30,880 options. 992 62 $179,280 $0 $56,080 Many teams are following analysts’ advice and adopting OpenJDK with supported and certified COST COMPARISON OF ORACLE JAVA VERSUS OPENJDK WITH OPENLOGIC SUPPORT builds from other vendors. the free OpenJDK license with OpenLogic support. Whether you have a OpenLogic can help organizations make the small or large core user base, the savings are substantial. move from Oracle Java to a supported OpenJDK The above comparison assumes the following: model with the following: • Most servers have dual, octa-core CPUs for a total • Free, certified and supported builds of of 16 cores. OpenJDK available at openlogic.com/ • The average user is in the 500 – 999 core tier priced openjdk-downloads. at $20/core/month (based on most recent Oracle Java • Enterprise support for any Java, including SE Subscription Global Price List). builds from other vendors. • The average customer has negotiated a 25% discount • Migration services to help you move seam- from Oracle. lessly from Oracle to OpenJDK. Java Support from OpenLogic Achieve Cost-Savings with Supported OpenJDK OpenLogic offers commercial support for all Java distributions, includ- ing Adopt OpenJDK, IBM, and Oracle’s Java. Based on the price of an Oracle Java SE subscription, which includes licensing and support, we’ve put Java support from OpenLogic includes security patches and bug fixes, together a conservative estimate of the annual in addition to guidance for the usage and administration of Java and the cost savings you can expect when migrating to JVM.
    [Show full text]
  • A Post-Apocalyptic Sun.Misc.Unsafe World
    A Post-Apocalyptic sun.misc.Unsafe World http://www.superbwallpapers.com/fantasy/post-apocalyptic-tower-bridge-london-26546/ Chris Engelbert Twitter: @noctarius2k Jatumba! 2014, 2015, 2016, … Disclaimer This talk is not going to be negative! Disclaimer But certain things are highly speculative and APIs or ideas might change by tomorrow! sun.misc.Scissors http://www.underwhelmedcomic.com/wp-content/uploads/2012/03/runningdude.jpg sun.misc.Unsafe - What you (don’t) know sun.misc.Unsafe - What you (don’t) know • Internal class (sun.misc Package) sun.misc.Unsafe - What you (don’t) know • Internal class (sun.misc Package) sun.misc.Unsafe - What you (don’t) know • Internal class (sun.misc Package) • Used inside the JVM / JRE sun.misc.Unsafe - What you (don’t) know • Internal class (sun.misc Package) • Used inside the JVM / JRE // Unsafe mechanics private static final sun.misc.Unsafe U; private static final long QBASE; private static final long QLOCK; private static final int ABASE; private static final int ASHIFT; static { try { U = sun.misc.Unsafe.getUnsafe(); Class<?> k = WorkQueue.class; Class<?> ak = ForkJoinTask[].class; example: QBASE = U.objectFieldOffset (k.getDeclaredField("base")); java.util.concurrent.ForkJoinPool QLOCK = U.objectFieldOffset (k.getDeclaredField("qlock")); ABASE = U.arrayBaseOffset(ak); int scale = U.arrayIndexScale(ak); if ((scale & (scale - 1)) != 0) throw new Error("data type scale not a power of two"); ASHIFT = 31 - Integer.numberOfLeadingZeros(scale); } catch (Exception e) { throw new Error(e); } } } sun.misc.Unsafe
    [Show full text]
  • Openjdk – the Future of Open Source Java on GNU/Linux
    OpenJDK – The Future of Open Source Java on GNU/Linux Dalibor Topić Java F/OSS Ambassador Blog aggregated on http://planetjdk.org Java Implementations Become Open Source Java ME, Java SE, and Java EE 2 Why now? Maturity Java is everywhere Adoption F/OSS growing globally Innovation Faster progress through participation 3 Why GNU/Linux? Values Freedom as a core value Stack Free Software above and below the JVM Demand Increasing demand for Java integration 4 Who profits? Developers New markets, new possibilities Customers More innovations, reduced risk Sun Mindshare, anchoring Java in GNU/Linux 5 License + Classpath GPL v2 Exception • No proprietary forks (for SE, EE) • Popular & trusted • Programs can have license any license • Compatible with • Improvements GNU/Linux remain in the community • Fostering adoption • FSFs license for GNU Classpath 6 A Little Bit Of History Jun 1996: Work on gcj starts Nov 1996: Work on Kaffe starts Feb 1998: First GNU Classpath Release Mar 2000: GNU Classpath and libgcj merge Dec 2002: Eclipse runs on gcj/Classpath Oct 2003: Kaffe switches to GNU Classpath Feb 2004: First FOSDEM Java Libre track Apr 2004: Richard Stallman on the 'Java Trap' Jan 2005: OpenOffice.org runs on gcj Mai 2005: Work on Harmony starts 7 Sun & Open Source Java RIs Juni 2005: Java EE RI Glassfish goes Open Source Mai 2006: First Glassfish release Mai 2006: Java announced to go Open Source November 2006: Java ME RI PhoneME goes Open Source November 2006: Java SE RI Hotspot und Javac go Open Source Mai 2007: The rest of Java SE follows suit 8 Status: JavaOne, Mai 2007 OpenJDK can be fully built from source, 'mostly' Open Source 25,169 Source code files 894 (4%) Binary files (“plugs”) 1,885 (8%) Open Source, though not GPLv2 The rest is GPLv2 (+ CP exception) Sun couldn't release the 4% back then as free software.
    [Show full text]
  • Fedora Core, Java™ and You
    Fedora Core, Java™ and You Gary Benson Software Engineer What is Java? The word ªJavaº is used to describe three things: The Java programming language The Java virtual machine The Java platform To support Java applications Fedora needs all three. What Fedora uses: GCJ and ECJ GCJ is the core of Fedora©s Java support: GCJ includes gcj, a compiler for the Java programming language. GCJ also has a runtime and class library, collectively called libgcj. The class library is separately known as GNU Classpath. ECJ is the Eclipse Compiler for Java: GCJ©s compiler gcj is not used for ªtraditionalº Java compilation. More on that later... Why libgcj? There are many free Java Virtual machines: Cacao, IKVM, JamVM, Jikes RVM, Kaffe, libgcj, Sable VM, ... There are two main reasons Fedora uses libgcj: Availability on many platforms. Ability to use precompiled native code. GNU Classpath Free core class library for Java virtual machines and compilers. The JPackage Project A collection of some 1,600 Java software packages for Linux: Distribution-agnostic RPM packages. Both runtimes/development kits and applications. Segregation between free and non-free packages. All free packages built entirely from source. Multiple runtimes/development kits may be installed. Fedora includes: JPackage-compatible runtime and development kit packages. A whole bunch of applications. JPackage JOnAS Fedora©s Java Compilers gcj can operate in several modes: Java source (.java) to Java bytecode (.class) Java source (.java) to native machine code (.o) Java bytecode (.class, .jar) to native machine code (.o) In Fedora: ECJ compiles Java source to bytecode. gcj compiles that bytecode to native machine code.
    [Show full text]
  • Java in Embedded Linux Systems
    Java in Embedded Linux Systems Java in Embedded Linux Systems Thomas Petazzoni / Michael Opdenacker Free Electrons http://free-electrons.com/ Created with OpenOffice.org 2.x Java in Embedded Linux Systems © Copyright 2004-2007, Free Electrons, Creative Commons Attribution-ShareAlike 2.5 license http://free-electrons.com Sep 15, 2009 1 Rights to copy Attribution ± ShareAlike 2.5 © Copyright 2004-2008 You are free Free Electrons to copy, distribute, display, and perform the work [email protected] to make derivative works to make commercial use of the work Document sources, updates and translations: Under the following conditions http://free-electrons.com/articles/java Attribution. You must give the original author credit. Corrections, suggestions, contributions and Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under a license translations are welcome! identical to this one. For any reuse or distribution, you must make clear to others the license terms of this work. Any of these conditions can be waived if you get permission from the copyright holder. Your fair use and other rights are in no way affected by the above. License text: http://creativecommons.org/licenses/by-sa/2.5/legalcode Java in Embedded Linux Systems © Copyright 2004-2007, Free Electrons, Creative Commons Attribution-ShareAlike 2.5 license http://free-electrons.com Sep 15, 2009 2 Best viewed with... This document is best viewed with a recent PDF reader or with OpenOffice.org itself! Take advantage of internal
    [Show full text]