Die Java-Plattform bietet viele Vorteile für die schnelle Entwicklung komplexer Software. Für die Ausführung des Java-Bytecodes auf eingebetteten Systemen eignen sich insbesondere Java-(Bytecode)-Prozessoren, die den Java-Bytecode als nativen Befehlssatz unterstützen. Die vorliegende Arbeit untersucht detailliert die Gestaltung einer Mehrkernarchitektur für Java-Prozessoren zur effizienten Nutzung der auf Thread-Ebene ohnehin vorhandenen Parallelität eines Java-Programms. Für die Funktionalitäts- und Leistungsbewertung eines Prototyps wird eine eigene Trace-Architektur eingesetzt. Es wird eine hohe Leistungssteigerung bei nur geringem zusätzlichem Hardwareaufwand erzielt sowie eine höhere Leistung als bekannte alternative Ansätze erreicht.

Die Java-Plattform bietet viele Vorteile für die schnelle Entwicklung komplexer Software. Für die Ausführung des Java-Bytecodes auf eingebetteten Systemen eignen sich insbesondere Java-(Bytecode)-Prozessoren, die den Java-Bytecode als nativen Befehlssatz unterstützen. Die vorliegende Arbeit untersucht detailliert die Gestaltung einer Mehrkernarchitektur für Java-Prozessoren zur effizienten Nutzung der auf Thread-Ebene ohnehin vorhandenen Parallelität eines Java-Programms. Für die Funktionalitäts- und Leistungsbewertung eines Prototyps wird eine eigene Trace-Architektur eingesetzt. Es wird eine hohe Leistungssteigerung bei nur geringem zusätzlichem Hardwareaufwand erzielt sowie eine höhere Leistung als bekannte alternative Ansätze erreicht.

Computation with large-scale heterogeneous data typically requires universal traversal to search for all occurrences of a substructure that matches a possibly complex search pattern, whose context may be different in different places within the data. Both aspects cause difficulty for existing general-purpose programming languages, because these languages are designed for homogeneous data and have problems typing the different substructures in heterogeneous data, and the complex patterns to match with the substructures. Programmers either have to hard-code the structures and search patterns, preventing programs from being reusable and scalable, or have to use low-level untyped programming or programming with special-purpose query languages, opening the door to type mismatches that cause a high risk of program correctness and security problems. This thesis invents the concept of pattern structures, and proposes a general solution to the above problems - a programming technique using pattern structures. In this solution, well-typed pattern structures are defined to represent complex search patterns, and pattern searching over heterogeneous data is programmed with pattern parameters, in a statically-typed language that supports first-class typing of structures and patterns. The resulting programs are statically-typed, highly reusable for different data structures and different patterns, and highly scalable in terms of the complexity of data structures and patterns. Adding new kinds of patterns for an application no longer requires changing the language in use or creating new ones, but is only a programming task. The thesis demonstrates the application of this approach to, and its advantages in, two important examples of computation with heterogeneous data, i.e., XML data processing and Java bytecode analysis. / Thesis (Ph.D, Computing) -- Queen's University, 2007-08-27 09:43:38.888

Important aspects of the IoT concept include privacy and security. There are various examples from the past, where implementation of security was insuffi- cient, which allowed hackers to gain unauthorized access to tens of thousands of everyday objects connected to the Internet and abuse this power to par- alyze the communication over the Internet. In this thesis we designed and implemented the Glinior tool that allows to define the contracts between objects or components in the application, and ensures that the communi- cation between specified objects or components happens according to those contracts. The Glinior tool uses techniques of dynamic analysis to verify contracts defined by the user. This is done by using the JVMTI framework with combination of the ASM library for bytecode manipulation.

Both J2BP and PANDA tools verify compiled Java programs. By now, these tools are not able to process some programs with specific JVM bytecode instruction sequences in the correct way. We described these instruction sequences and proposed their transformations. We developed the new application, called BytecodeTransformer, based on these propositions. This application transforms compiled Java programs and replaces the problematic instruction sequences with some others. Usage of BytecodeTransformer enlarges the set of programs that can be verified by both J2BP and PANDA. We also evaluated BytecodeTransformer on several Java programs, including own tests and well-known open-source programs. These tests demonstrated the correct functionality of BytecodeTransformer. Powered by TCPDF (www.tcpdf.org)

This paper deals with the Java bytecode size optimization. It describes the Java Virtual Machine and the Java class file format. It also presents some tools for the bytecode manipulation. Using these tools, I have analyzed selected data and found sequences of instructions, that could be optimized. Based on the results of the analysis, I have designed and implemented methods for bytecode size optimization. The bytecode size of the selected data was reduced by roughly 25%.

The work describes methods and principles of decompilation, basic information about reverse engineering and its use in both software engineering and engineering in general. Furthermore, it introduces the decompiler developed within the Lissom project at BUT FIT. The goal of the work is to design and implement a retargetable decompiler for bytecode, which extends the original decompiler.

Abstract This paper introduces a new embedded Java multi-core architecture which shows a significantly better performance for a large number of cores than the related projects JopCMP and jamuth IP multi-core. The cores gain fast access to the shared heap by a fullduplex bus with pipelined transactions. Each core is equipped with local on-chip memory for the Java operand stack and the method cache to further reduce the memory bandwidth requirements. As opposed to the related projects, synchronization is supported on a per object-basis instead of a single lock. Load balancing is implemented in Java and requires no additional hardware. The multi-port memory manager includes an exact and fully concurrent garbage collector for automatic memory management. The design can be synthesized for a variable number of parallel cores and shows a linear increase in chip-space. Three different benchmarks demonstrate the very good scalability of our architecture. Due to limited chip-space on our evaluation platform, the core count could not be increased further than 8. But, we expect a smooth performance decrease.

Main memory remains a scarce computing resource. Even though main memory is becoming more abundant, software applications are inexorably engineered to consume as much memory as is available. For example, expert systems, scientific computing, data mining, and embedded systems commonly suffer from the lack of main memory availability. This thesis introduces JDiet, an innovative memory management system for Java applications. The goal of JDiet is to provide the developer with a highly configurable framework to reduce the memory footprint of a memory-constrained system, enabling it to operate on much larger working sets. Inspired by buffer management techniques common in modern database management systems, JDiet frees main memory by evicting non-essential data to a disk-based store. A buffer retains a fixed amount of managed objects in main memory. As non-resident objects are accessed, they are swapped from the store to the buffer using an extensible replacement policy. While the Java virtual machine naïvely delegates virtual memory management to the operating system, JDiet empowers the system designer to select both the managed data and replacement policy. Guided by compile-time configuration, JDiet performs aspect-oriented bytecode engineering, requiring no explicit coupling to the source or compiled code. The results of an experimental evaluation of the effectiveness of JDiet are reported. A JDiet-enabled XML DOM parser is capable of parsing and processing over 200% larger input documents by sacrificing less than an order of magnitude in performance.

A dynamic program analysis provides essential information during later phases of an application development. It helps with debugging, profiling, performance optimizations or vulnerability detection. Despite that, support for creating custom dynamic analysis tools, especially in the domain of managed languages, is rather limited. In this thesis, we present two systems to help improve application observability on the Java platform. DiSL is a language accompanied with a framework allowing simple and flexible instrumentation for the dynamic program analysis. DiSL provides high level abstractions to enable quick prototyping even for programmers not possessing a knowledge of Java internals. A skilled analysis developer gains full control over the instrumentation process, thus does not have to worry about unwanted allocations or hidden execution overhead. ShadowVM is a platform that provides isolation between the observed application and the analysis environment. To reduce the amount of possible interactions between the analysis and the application, ShadowVM offloads analysis events out of the context of the application. Even though the isolation is the primary focus of the platform, ShadowVM introduces a number of techniques to stay performance comparable and provide a similar programming model as existing...