Java Virtual Machine Guide
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SJC – Small Java Compiler
SJC – Small Java Compiler User Manual Stefan Frenz Translation: Jonathan Brase original version: 2011/06/08 latest document update: 2011/08/24 Compiler Version: 182 Java is a registered trademark of Oracle/Sun Table of Contents 1 Quick introduction.............................................................................................................................4 1.1 Windows...........................................................................................................................................4 1.2 Linux.................................................................................................................................................5 1.3 JVM Environment.............................................................................................................................5 1.4 QEmu................................................................................................................................................5 2 Hello World.......................................................................................................................................6 2.1 Source Code......................................................................................................................................6 2.2 Compilation and Emulation...............................................................................................................8 2.3 Details...............................................................................................................................................9 -
Java (Programming Langua a (Programming Language)
Java (programming language) From Wikipedia, the free encyclopedialopedia "Java language" redirects here. For the natural language from the Indonesian island of Java, see Javanese language. Not to be confused with JavaScript. Java multi-paradigm: object-oriented, structured, imperative, Paradigm(s) functional, generic, reflective, concurrent James Gosling and Designed by Sun Microsystems Developer Oracle Corporation Appeared in 1995[1] Java Standard Edition 8 Update Stable release 5 (1.8.0_5) / April 15, 2014; 2 months ago Static, strong, safe, nominative, Typing discipline manifest Major OpenJDK, many others implementations Dialects Generic Java, Pizza Ada 83, C++, C#,[2] Eiffel,[3] Generic Java, Mesa,[4] Modula- Influenced by 3,[5] Oberon,[6] Objective-C,[7] UCSD Pascal,[8][9] Smalltalk Ada 2005, BeanShell, C#, Clojure, D, ECMAScript, Influenced Groovy, J#, JavaScript, Kotlin, PHP, Python, Scala, Seed7, Vala Implementation C and C++ language OS Cross-platform (multi-platform) GNU General Public License, License Java CommuniCommunity Process Filename .java , .class, .jar extension(s) Website For Java Developers Java Programming at Wikibooks Java is a computer programming language that is concurrent, class-based, object-oriented, and specifically designed to have as few impimplementation dependencies as possible.ble. It is intended to let application developers "write once, run ananywhere" (WORA), meaning that code that runs on one platform does not need to be recompiled to rurun on another. Java applications ns are typically compiled to bytecode (class file) that can run on anany Java virtual machine (JVM)) regardless of computer architecture. Java is, as of 2014, one of tthe most popular programming ng languages in use, particularly for client-server web applications, witwith a reported 9 million developers.[10][11] Java was originallyy developed by James Gosling at Sun Microsystems (which has since merged into Oracle Corporation) and released in 1995 as a core component of Sun Microsystems'Micros Java platform. -
The Java® Language Specification Java SE 8 Edition
The Java® Language Specification Java SE 8 Edition James Gosling Bill Joy Guy Steele Gilad Bracha Alex Buckley 2015-02-13 Specification: JSR-337 Java® SE 8 Release Contents ("Specification") Version: 8 Status: Maintenance Release Release: March 2015 Copyright © 1997, 2015, Oracle America, Inc. and/or its affiliates. 500 Oracle Parkway, Redwood City, California 94065, U.S.A. All rights reserved. Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners. The Specification provided herein is provided to you only under the Limited License Grant included herein as Appendix A. Please see Appendix A, Limited License Grant. To Maurizio, with deepest thanks. Table of Contents Preface to the Java SE 8 Edition xix 1 Introduction 1 1.1 Organization of the Specification 2 1.2 Example Programs 6 1.3 Notation 6 1.4 Relationship to Predefined Classes and Interfaces 7 1.5 Feedback 7 1.6 References 7 2 Grammars 9 2.1 Context-Free Grammars 9 2.2 The Lexical Grammar 9 2.3 The Syntactic Grammar 10 2.4 Grammar Notation 10 3 Lexical Structure 15 3.1 Unicode 15 3.2 Lexical Translations 16 3.3 Unicode Escapes 17 3.4 Line Terminators 19 3.5 Input Elements and Tokens 19 3.6 White Space 20 3.7 Comments 21 3.8 Identifiers 22 3.9 Keywords 24 3.10 Literals 24 3.10.1 Integer Literals 25 3.10.2 Floating-Point Literals 31 3.10.3 Boolean Literals 34 3.10.4 Character Literals 34 3.10.5 String Literals 35 3.10.6 Escape Sequences for Character and String Literals 37 3.10.7 The Null Literal 38 3.11 Separators -
Building Useful Program Analysis Tools Using an Extensible Java Compiler
Building Useful Program Analysis Tools Using an Extensible Java Compiler Edward Aftandilian, Raluca Sauciuc Siddharth Priya, Sundaresan Krishnan Google, Inc. Google, Inc. Mountain View, CA, USA Hyderabad, India feaftan, [email protected] fsiddharth, [email protected] Abstract—Large software companies need customized tools a specific task, but they fail for several reasons. First, ad- to manage their source code. These tools are often built in hoc program analysis tools are often brittle and break on an ad-hoc fashion, using brittle technologies such as regular uncommon-but-valid code patterns. Second, simple ad-hoc expressions and home-grown parsers. Changes in the language cause the tools to break. More importantly, these ad-hoc tools tools don’t provide sufficient information to perform many often do not support uncommon-but-valid code code patterns. non-trivial analyses, including refactorings. Type and symbol We report our experiences building source-code analysis information is especially useful, but amounts to writing a tools at Google on top of a third-party, open-source, extensible type-checker. Finally, more sophisticated program analysis compiler. We describe three tools in use on our Java codebase. tools are expensive to create and maintain, especially as the The first, Strict Java Dependencies, enforces our dependency target language evolves. policy in order to reduce JAR file sizes and testing load. The second, error-prone, adds new error checks to the compilation In this paper, we present our experience building special- process and automates repair of those errors at a whole- purpose tools on top of the the piece of software in our codebase scale. -
Towards Performance Measurements for the Java Virtual Machine's
Towards Performance Measurements for the Java Virtual Machine’s invokedynamic Chanwit Kaewkasi School of Computer Engineering Suranaree University of Technology Nakhon Ratchasima, Thailand 30000 [email protected] ABSTRACT JVML are strongly typed. Every symbol is linked before This paper presents a study of a Java Virtual Machine prototype executing a referencing instruction [15]. In the JVM, there are from the Da Vinci Machine project, defined by JSR 292. It four instructions for invoking different kinds of Java method describes binary translation techniques to prepare benchmarks to calls. These instructions serve Java programs perfectly, but not run on the invokedynamic mode of the prototype, resulting that well for other languages that use the JVM as their runtime in the invokedynamic version of the SciMark 2.0 suite. systems [4], [5], [8], [11], [12]. Benchmark preparation techniques presented in this paper are The Da Vinci Machine project [3], also known as the Multi- proven to be useful as the invokedynamic version of Language Virtual Machine (MLVM), is an effort to investigate benchmark programs successfully identified strange slowness and develop prototypes that support a new bytecode instruction, behavior of the invokedynamic mode of the server virtual invokedynamic [15], to extend the Java Virtual Machine machine. (JVM) to other languages, beside the Java language itself. Surprisingly, benchmarking results show that the invoke- Recently, several language implementers have adapted the JVM dynamic mode with direct method handles on the server as a runtime system for their languages, which include virtual machine is just 2-5 times slower than native Java JavaScript [11], JRuby [12], Scala [13], Groovy [8], Clojure [4] invocations, except the Monte Carlo benchmark. -
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 | -
SUBJECT-COMPUTER CLASS-12 CHAPTER 9 – Compiling and Running Java Programs
SUBJECT-COMPUTER CLASS-12 CHAPTER 9 – Compiling and Running Java Programs Introduction to Java programming JAVA was developed by Sun Microsystems Inc in 1991, later acquired by Oracle Corporation. It was developed by James Gosling and Patrick Naughton. It is a simple programming language. Writing, compiling and debugging a program is easy in java. It helps to create modular programs and reusable code. Bytecode javac compiler of JDK compiles the java source code into bytecode so that it can be executed by JVM. The bytecode is saved in a .class file by compiler. Java Virtual Machine (JVM) This is generally referred as JVM. Before, we discuss about JVM lets see the phases of program execution. Phases are as follows: we write the program, then we compile the program and at last we run the program. 1) Writing of the program is of course done by java programmer. 2) Compilation of program is done by javac compiler, javac is the primary java compiler included in java development kit (JDK). It takes java program as input and generates java bytecode as output. 3) In third phase, JVM executes the bytecode generated by compiler. This is called program run phase. So, now that we understood that the primary function of JVM is to execute the bytecode produced by compiler. Characteristics of Java Simple Java is very easy to learn, and its syntax is simple, clean and easy to understand. Multi-threaded Multithreading capabilities come built right into the Java language. This means it is possible to build highly interactive and responsive apps with a number of concurrent threads of activity. -
Coqjvm: an Executable Specification of the Java Virtual Machine Using
CoqJVM: An Executable Specification of the Java Virtual Machine using Dependent Types Robert Atkey LFCS, School of Informatics, University of Edinburgh Mayfield Rd, Edinburgh EH9 3JZ, UK [email protected] Abstract. We describe an executable specification of the Java Virtual Machine (JVM) within the Coq proof assistant. The principal features of the development are that it is executable, meaning that it can be tested against a real JVM to gain confidence in the correctness of the specification; and that it has been written with heavy use of dependent types, this is both to structure the model in a useful way, and to constrain the model to prevent spurious partiality. We describe the structure of the formalisation and the way in which we have used dependent types. 1 Introduction Large scale formalisations of programming languages and systems in mechanised theorem provers have recently become popular [4–6, 9]. In this paper, we describe a formalisation of the Java virtual machine (JVM) [8] in the Coq proof assistant [11]. The principal features of this formalisation are that it is executable, meaning that a purely functional JVM can be extracted from the Coq development and – with some O’Caml glue code – executed on real Java bytecode output from the Java compiler; and that it is structured using dependent types. The motivation for this development is to act as a basis for certified consumer- side Proof-Carrying Code (PCC) [12]. We aim to prove the soundness of program logics and correctness of proof checkers against the model, and extract the proof checkers to produce certified stand-alone tools. -
Chapter 9: Java
,ch09.6595 Page 159 Friday, March 25, 2005 2:47 PM Chapter 9 CHAPTER 9 Java Many Java developers like Integrated Development Environments (IDEs) such as Eclipse. Given such well-known alternatives as Java IDEs and Ant, readers could well ask why they should even think of using make on Java projects. This chapter explores the value of make in these situations; in particular, it presents a generalized makefile that can be dropped into just about any Java project with minimal modification and carry out all the standard rebuilding tasks. Using make with Java raises several issues and introduces some opportunities. This is primarily due to three factors: the Java compiler, javac, is extremely fast; the stan- dard Java compiler supports the @filename syntax for reading “command-line param- eters” from a file; and if a Java package is specified, the Java language specifies a path to the .class file. Standard Java compilers are very fast. This is primarily due to the way the import directive works. Similar to a #include in C, this directive is used to allow access to externally defined symbols. However, rather than rereading source code, which then needs to be reparsed and analyzed, Java reads the class files directly. Because the symbols in a class file cannot change during the compilation process, the class files are cached by the compiler. In even medium-sized projects, this means the Java com- piler can avoid rereading, parsing, and analyzing literally millions of lines of code compared with C. A more modest performance improvement is due to the bare mini- mum of optimization performed by most Java compilers. -
Solution Brief JVM Performance Monitoring
Solution Brief Monitoring the Health & Performance of Java Virtual Machines (JVM) Total Performance Visibility JVM: The Cornerstone of Java Enterprise Applications The Java Virtual Machine (JVM) forms the core of the Java application architecture. It plays the crucial role of interpreting and translating Java byte code into operations on the host platform. Since Java middleware (application servers such as Tomcat, JBoss EAP, JBoss AS, WildFly, WebSphere, and WebLogic) runs on the JVM, a performance issue at the JVM level has a major impact on business services supported by it. Monitoring of the JVM must be an integral part of any Java application performance monitoring strategy. IT Ops and DevOps teams use JVM Key Benefits performance metrics to troubleshoot server-side bottlenecks. Developers and architects can also benefit from JVM monitoring by uncovering code- Proactively detect and resolve level issues. Java application problems to ensure high service uptime and business continuity Key JVM Performance Questions to Answer Troubleshoot faster: Real-time • Is there any runaway thread hogging the CPU? Which line of code is it alerts pinpoint the exact line executing, in which class, and which method? of code that is impacting Java • Is the JVM heap and non-heap memory sized correctly? applications • Are there any out-of-memory-exceptions or memory leaks? In-depth analytics enable architects to optimize Java • When does garbage collection happen, and how much memory is applications to scale and support freed up each time? additional users • Are there any thread deadlocks happening that are causing Single pane of glass to monitor application processing to be hung? everything Java—from application server, JVM and database, all the way down to server and storage End-to-End JVM Monitoring with eG Enterprise infrastructure eG Enterprise is a comprehensive performance monitoring, diagnosis and reporting solution for Java application infrastructures. -
A Study of Cache Performance in Java Virtual Machines, the University of Texas at Austin, 2002
Cache Performance in Java Virtual Machines: A Study of Constituent Phases Anand S. Rajan, Juan Rubio and Lizy K. John Laboratory for Computer Architecture Department of Electrical & Computer Engineering The University of Texas at Austin (arajan, jrubio,[email protected]) Abstract This paper studies the cache performance of Java programs in the interpreted and just-in- time (JIT) modes by analyzing memory reference traces of the SPECjvm98 applications with the Latte JVM. Specifically, we study the cache performance of the different components of the JVM (class loader, the execution engine and the garbage collector). Poor data cache performance in JITs is caused by code installation, and the data write miss rate can be as high as 70% in the execution engine. In addition, this code installation also causes deterioration in performance of the instruction cache during execution of translated code. We also believe that there is considerable interference between data accesses of the garbage collector and that of the compiler-translator execution engine of the JIT mode. We observe that the miss percentages in the garbage collection phase are of the order of 60% for the JIT mode; we believe that interference between data accesses of the garbage collector and the JIT execution engine lead to further deterioration of the data cache performance wherever the contribution of the garbage collector is significant. We observe that an increase in cache sizes does not substantially improve performance in the case of data cache writes, which is identified to be the principal performance bottleneck in JITs. 1 1. Introduction Java[1] is a widely used programming language due to the machine independent nature of bytecodes. -
Java and C I CSE 351 Autumn 2016
L26: JVM CSE351, Spring 2018 Java Virtual Machine CSE 351 Spring 2018 Model of a Computer “Showing the Weather” Pencil and Crayon on Paper Matai Feldacker-Grossman, Age 4 May 22, 2018 L26: JVM CSE351, Spring 2018 Roadmap C: Java: Memory & data Integers & floats car *c = malloc(sizeof(car)); Car c = new Car(); x86 assembly c->miles = 100; c.setMiles(100); c->gals = 17; c.setGals(17); Procedures & stacks float mpg = get_mpg(c); float mpg = Executables free(c); c.getMPG(); Arrays & structs Memory & caches Assembly get_mpg: Processes language: pushq %rbp Virtual memory movq %rsp, %rbp ... Memory allocation popq %rbp Java vs. C ret OS: Machine 0111010000011000 code: 100011010000010000000010 1000100111000010 110000011111101000011111 Computer system: 2 L26: JVM CSE351, Spring 2018 Implementing Programming Languages Many choices in how to implement programming models We’ve talked about compilation, can also interpret Interpreting languages has a long history . Lisp, an early programming language, was interpreted Interpreters are still in common use: . Python, Javascript, Ruby, Matlab, PHP, Perl, … Interpreter Your source code implementation Your source code Binary executable Interpreter binary Hardware Hardware 3 L26: JVM CSE351, Spring 2018 An Interpreter is a Program Execute (something close to) the source code directly Simpler/no compiler – less translation More transparent to debug – less translation Easier to run on different architectures – runs in a simulated environment that exists only inside the interpreter process . Just port the interpreter (program), not the program-intepreted Slower and harder to optimize 4 L26: JVM CSE351, Spring 2018 Interpreter vs. Compiler An aspect of a language implementation . A language can have multiple implementations . Some might be compilers and other interpreters “Compiled languages” vs.