Java Class Annotation Example
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How Can Java Class Files Be Decompiled?
HOW CAN JAVA CLASS FILES BE DECOMPILED? David Foster Chamblee High School 11th Grade Many computer science courses feature building a compiler as a final project. I have decided to take a spin on the idea and instead develop a decompiler. Specifically, I decided to write a Java decompiler because: one, I am already familiar with the Java language, two, the language syntax does not suffer from feature-bloat, and three, there do not appear to be many Java decompilers currently on the market. I have approached the task of writing a decompiler as a matter of translating between two different languages. In our case, the source language is Java Virtual Machine (VM) Bytecode, and the target language is the Java Language. As such, our decompiler will attempt to analyze the semantics of the bytecode and convert it into Java source code that has equivalent semantics. A nice sideeffect of this approach is that our decompiler will not be dependent upon the syntax of the bytecodes, the compiler used to generate the bytecodes, or the source language (possibly not Java). It will only care whether a class-file’s semantics can be represented in the Java language. Decompilation is divided up into six phases: 1. Read opcodes 2. Interpret opcode behavior 3. Identify Java-language “idioms” 4. Identify patterns of control-flow 5. Generate Java-language statements 6. Format and output to file The first four phases will be discussed in detail within this paper, as they were the primary focus of my research. Further details pertaining to these phases can be gleaned from the accompanying log book. -
Advanced Programming for the Java(TM) 2 Platform
Advanced Programming for the Java(TM) 2 Platform Training Index Advanced Programming for the JavaTM 2 Platform By Calvin Austin and Monica Pawlan November 1999 [CONTENTS] [NEXT>>] [DOWNLOAD] Requires login As an experienced developer on the JavaTM platform, you undoubtedly know how fast moving and comprehensive the Early Access platform is. Its many application programming interfaces (APIs) Downloads provide a wealth of functionality for all aspects of application and system-level programming. Real-world developers never use one Bug Database or two APIs to solve a problem, but bring together key Submit a Bug functionality spanning a number of APIs. Knowing which APIs you View Database need, which parts of which APIs you need, and how the APIs work together to create the best solution can be a daunting task. Newsletters Back Issues To help you navigate the Java APIs and fast-track your project Subscribe development time, this book includes the design, development, test, and deployment phases for an enterprise-worthy auction Learning Centers application. While the example application does not cover every Articles possible programming scenario, it explores many common Bookshelf situations and the discussions leave you with a solid methodology Code Samples for designing and building your own solutions. New to Java Question of the Week This book is for developers with more than a beginning level of Quizzes understanding of writing programs in the Java programming Tech Tips language. The example application is written with the Java® 2 Tutorials platform APIs and explained in terms of functional hows and whys, so if you need help installing the Java platform, setting up your Forums environment, or getting your first application to work, you should first read a more introductory book such as Essentials of the Java Programming Language: A Hands-On Guide or The Java Tutorial. -
Information Retrieval from Java Archive Format
Eötvös Loránd University Faculty of Informatics Department of Programming Languages and Compilers Information retrieval from Java archive format Supervisor: Author: Dr. Zoltán Porkoláb Bálint Kiss Associate Professor Computer Science MSc Budapest, 2017 Abstract During the course of my work, I contributed to CodeCompass, an open source code comprehension tool made for making codebase of software projects written in C, C++ and Java more understandable through navigation and visualization. I was tasked with the development of a module for recovering code information of Java classes in JAR files. This document details background concepts required for reverse- engineering Java bytecode, creating a prototype JAR file reader and how this solu- tion could be integrated to CodeCompass. First, I studied the structure of JAR format and how class files are stored in it. I looked into the Java Class file structure and how bytecode contained in class gets interpreted by the Java Virtual Machine. I also looked at existing decompilers and what bytecode libraries are. I created a proof-of-concept prototype that reads compiled classes from JAR file and extracts code information. I first showcased the use of Java Reflection API, then the use of Apache Commons Byte Code Engineering Library, a third-party bytecode library used for extracting and representing parts of Java class file as Java objects. Finally, I examined how CodeCompass works, how part of the prototype could be integrated into it and demonstrated the integration through parsing of a simple JAR file. i Acknowledgements I would like to thank Dr. Zoltán Porkoláb, Associate Professor of the Department of Programming Languages and Compilers at the Faculty of Informatics for admit- ting me to the CodeCompass project, supplying the thesis topic and helping with the documentation. -
Annotation File Format Specification
Annotation File Format Specification https://checkerframework.org/annotation-file-utilities/ September 1, 2021 Contents 1 Purpose: External storage of annotations 1 2 Grammar 2 2.1 Grammar conventions . 2 2.2 Java file grammar . 2 2.2.1 Package definitions . 3 2.2.2 Class definitions . 3 2.2.3 Field definitions . 5 2.2.4 Method definitions . 5 2.3 Bytecode Locations . 6 2.3.1 Bytecode offsets . 7 2.3.2 Source code indexes . 7 2.3.3 Code locations grammar . 7 2.3.4 AST paths . 9 2.4 Annotations . 15 2.4.1 Annotation definitions . 15 2.4.2 Annotation uses . 15 3 Example 17 4 Types and values 17 5 Alternative formats 19 1 Purpose: External storage of annotations Java annotations are meta-data about Java program elements, as in \@Deprecated class Date f ... g". Ordinarily, Java annotations are written in the source code of a .java Java source file. When javac compiles the source code, it inserts the annotations in the resulting .class file (as \attributes"). Sometimes, it is convenient to specify the annotations outside the source code or the .class file. • When source code is not available, a textual file provides a format for writing and storing annotations that is much easier to read and modify than a .class file. Even if the eventual purpose is to insert the annotations in the .class file, the annotations must be specified in some textual format first. • Even when source code is available, sometimes it should not be changed, yet annotations must be stored somewhere for use by tools. -
Aspectj in Action, Second Edition
Introducing AspectJ This chapter covers ■ Writing an AspectJ “Hello, world!” application ■ Becoming familiar with the AspectJ language ■ Weaving mechanisms ■ Integrating with Spring In chapter 1, we focused on general concepts in AOP. With those behind us, we can now look at one specific AOP implementation: AspectJ. AspectJ is an aspect- oriented extension to the Java programming language. Like any AOP implementa- tion, AspectJ consists of two parts: the language specification, which defines the grammar and semantics of the language; and the language implementation, which includes weavers that take various forms such as a compiler and a linker. A weaver produces byte code that conforms to the Java byte-code specification, allowing any compliant Java virtual machine (VM) to execute those class files. The language implementation also offers support for integrated development environments (IDEs), to simplify building and debugging applications. AspectJ started and initially grew as a special language that extends the Java lan- guage with new keywords. It also provided a special compiler that could understand those extensions. But recently, a lot has changed in its form as a language, as well as 27 Licensed to Manning Marketing <[email protected]> 28 CHAPTER 2 Introducing AspectJ in the weaver. First, AspectJ offers an alternative syntax based on the Java annotation facil- ity to express crosscutting constructs. This lets you use a plain Java compiler instead of the special compiler. Second, AspectJ offers new options for weaving classes with aspects. Finally, it has gained a strong foothold in the Spring Framework with several integration options. All these changes have made adoption of AspectJ easier than ever before. -
Advanced-Java.Pdf
Advanced java i Advanced java Advanced java ii Contents 1 How to create and destroy objects 1 1.1 Introduction......................................................1 1.2 Instance Construction.................................................1 1.2.1 Implicit (Generated) Constructor.......................................1 1.2.2 Constructors without Arguments.......................................1 1.2.3 Constructors with Arguments........................................2 1.2.4 Initialization Blocks.............................................2 1.2.5 Construction guarantee............................................3 1.2.6 Visibility...................................................4 1.2.7 Garbage collection..............................................4 1.2.8 Finalizers...................................................5 1.3 Static initialization..................................................5 1.4 Construction Patterns.................................................5 1.4.1 Singleton...................................................6 1.4.2 Utility/Helper Class.............................................7 1.4.3 Factory....................................................7 1.4.4 Dependency Injection............................................8 1.5 Download the Source Code..............................................9 1.6 What’s next......................................................9 2 Using methods common to all objects 10 2.1 Introduction...................................................... 10 2.2 Methods equals and hashCode........................................... -
Inversion of Control in Spring – Using Annotation
Inversion of Control in Spring – Using Annotation In this chapter, we will configure Spring beans and the Dependency Injection using annotations. Spring provides support for annotation-based container configuration. We will go through bean management using stereotypical annotations and bean scope using annotations. We will then take a look at an annotation called @Required, which allows us to specify which dependencies are actually required. We will also see annotation-based dependency injections and life cycle annotations. We will use the autowired annotation to wire up dependencies in the same way as we did using XML in the previous chapter. You will then learn how to add dependencies by type and by name. We will also use qualifier to narrow down Dependency Injections. We will also understand how to perform Java-based configuration in Spring. We will then try to listen to and publish events in Spring. We will also see how to reference beans using Spring Expression Language (SpEL), invoke methods using SpEL, and use operators with SpEL. We will then discuss regular expressions using SpEL. Spring provides text message and internationalization, which we will learn to implement in our application. Here's a list of the topics covered in this chapter: • Container configuration using annotations • Java-based configuration in Spring • Event handling in Spring • Text message and internationalization [ 1 ] Inversion of Control in Spring – Using Annotation Container configuration using annotation Container configuration using Spring XML sometimes raises the possibility of delays in application development and maintenance due to size and complexity. To solve this issue, the Spring Framework supports container configuration using annotations without the need of a separate XML definition. -
Type Annotations Specification
Type Annotations Specification (JSR 308) Michael D. Ernst [email protected] May 2, 2013 The JSR 308 webpage is http://types.cs.washington.edu/jsr308/. It contains the latest version of this document, along with other information such as a FAQ, the reference implementation, and sample annotation processors. Contents 1 Introduction 2 2 Java language syntax extensions 2 2.1 Source locations for annotations on types . 2 2.1.1 Implicit type uses are not annotatable . 5 2.1.2 Not all type names are annotatable . 5 2.2 Java language grammar changes . 6 2.2.1 Syntax of array annotations . 8 2.2.2 Syntax of annotations on qualified types . 9 2.3 Target meta-annotations for type annotations . 9 3 Class file format extensions 11 3.1 The type annotation structure . 12 3.2 The target type field: the type of annotated element . 13 3.3 The target info field: identifying a program element . 13 3.3.1 Type parameters . 13 3.3.2 Class supertypes: extends and implements clauses . 14 3.3.3 Type parameter bounds . 14 3.3.4 Method return type, receiver, and fields . 15 3.3.5 Method formal parameters . 15 3.3.6 throws clauses . 15 3.3.7 Local variables and resource variables . 15 3.3.8 Exception parameters (catch clauses) . 16 3.3.9 Type tests, object creation, and method/constructor references . 16 3.3.10 Casts and type arguments to constructor/method invocation/references . 16 3.4 The type path structure: Identifying part of a compound type . 17 A Examples of classfile structure 18 A.1 Examples of type parameter bounds . -
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. -
Hibernate Tools
APPENDIX A ■ ■ ■ More Advanced Features In this appendix, we discuss some of the features that, strictly speaking, lie outside the scope of this book, but that you should be aware of if you go on to use Hibernate in more depth. Managed Versioning and Optimistic Locking While we have saved versioning for this appendix’s discussion of advanced features, it is actually quite straightforward to understand and apply. Consider the following scenario: • Client A loads and edits a record. • Client B loads and edits the same record. • Client A commits its edited record data. • Client B commits its differently edited record data. While the scenario is simple, the problems it presents are not. If Client A establishes a transaction, then Client B may not be able to load and edit the same record. Yet in a web environment, it is not unlikely that Client A will close a browser window on the open record, never committing or canceling the transaction, so that the record remains locked until the session times out. Clearly this is not a satisfactory solution. Usually, you will not want to permit the alternative scenario, in which no locking is used, and the last person to save a record wins! The solution, versioning, is essentially a type of optimistic locking (see Chapter 8). When any changes to an entity are stored, a version column is updated to reflect the fact that the entity has changed. When a subsequent user tries to commit changes to the same entity, the original version number will be compared against the current value—if they differ, the commit will be rejected. -
Using Other Tools with Jython
A P P E N D I X A Using Other Tools with Jython The primary focus of this appendix is to provide information on using some external Python packages with Jython, as well as providing information regarding the Jython registry. In some circumstances, the tools must be used or installed a bit differently on Jython than on CPython, and those differences will be noted. Because there is a good deal of documentation on the usage of these tools available on the web, this appendix will focus on using the tool specifically with Jython. However, relevant URLs will be cited for finding more documentation on each of the topics. The Jython Registry Because there is no good platform-independent equivalent of the Windows Registry or Unix environment variables, Java has its own environment variable namespace. Jython acquires its namespace from the following sources (later sources override defaults found in earlier places): • The Java system properties, typically passed in on the command line as options to the java interpreter. • The Jython “registry” file, containing prop=value pairs. Read on for the algorithm Jython uses to find the registry file. • The user’s personal registry file, containing similarly formatted prop/value pairs. The user’s registry file can be found at "user.home"+"/.jython" • Jython properties specified on the command line as options to the Jython class. See the -D option to the interpreter. Registry Properties The following properties are recognized by Jython. There may be others that aren’t documented here; consult the comments in registry file for details. python.cachedir The directory to use for caches—currently just package information. -
Vysoke´Ucˇenítechnicke´V Brneˇ Automaticka´Tvorba
VYSOKE´ UCˇ ENI´ TECHNICKE´ V BRNEˇ BRNO UNIVERSITY OF TECHNOLOGY FAKULTA INFORMACˇ NI´CH TECHNOLOGII´ U´ STAV POCˇ ´ITACˇ OVE´ GRAFIKY A MULTIME´ DII´ FACULTY OF INFORMATION TECHNOLOGY DEPARTMENT OF COMPUTER GRAPHICS AND MULTIMEDIA AUTOMATICKA´ TVORBA GRAFICKE´ HO ROZHRANI´ PRO VZDA´ LENY´ PRˇ ´ISTUP AUTOMATIC USER INTERFACE DESIGN FOR REMOTE ACCESS DIPLOMOVA´ PRA´ CE MASTER’S THESIS AUTOR PRA´ CE Bc. JAN KORITˇA´ K AUTHOR VEDOUCI´ PRA´ CE Doc. Dr. Ing. PAVEL ZEMCˇ ´IK SUPERVISOR BRNO 2011 Abstrakt Tato práce zkoumá možnosti abstrakce grafického uživatelského rozhraní a automatizace procesu jeho návrhu a tvorby za provozu aplikace. Dùraz je kladen na možnost ovládání apli- kace na dálku pøes počítačovou síť a tedy na delegaci procesu tvorby rozhraní na vzdálený stroj obsluhovaný uživatelem. Práce analyzuje souèasné přístupy a metody pro generování rozhraní. V rámci práce byl navržen a implementován systém pro automatické generování uživatelského rozhraní vzdálené aplikace na základě specifikovaného datového modelu. Abstract This thesis explores the possibilities of abstraction of graphical user interface and auto- mation of its design and development process at runtime. Emphasis is placed on possibility of remote control over computer network and accordingly on delegation of the interface creation on the human operated remote machine. The thesis analyzes contemporary appro- aches to and methods of interface generation. As a goal of the thesis a system for automatic user interface generation for remote applications was designed and implemented.