Safe and atomic run-time code evolution for Java and its application to dynamic AOP

Abstract

Dynamic updates to running programs improve development productivity and reduce downtime of long-running applications. This feature is however severely limited in current virtual machines for object-oriented languages. In particular, changes to classes often apply only to methods invoked after a class change, but not to active methods on the call stack of threads. Additionally, adding and removing methods as well as fields is often not supported. We present a novel programming model for safe and atomic code updates of Java programs that also updates methods that are currently executed. We introduce safe update regions and pause threads only there before an update. We automatically convert the stack frames to suit the new versions of the methods. Our implementation is based on a production-quality Java virtual machine. Additionally, we present SafeWeave, a dynamic aspect-oriented programming system that exposes the atomic code updates through a high-level programming model. AspectJ advice can be added to and removed from a running application.Changes are atomic and correctness is guaranteed even though weaving happens in parallel to program execution, and the system fully supports the dynamic class loading of Java. We show that the enhanced evolution features do not incur any performance penalty before and after version changes.

Dynamic Software Updates for Unmodified Browsers through Multi-Version Execution

“…The problem of Dynamic Software Updating (DSU) has been a focus of past research, resulting in DSU systems for programs written in popular languages such as C [Chen et al 2007;Giuffrida et al 2013aGiuffrida et al , 2014Giuffrida et al , 2013bHayden et al 2012] and Java [Kabanov and Vene 2014;Pina and Cachopo 2012;Pina et al 2014;Subramanian et al 2009;Würthinger et al 2011Würthinger et al , 2010. Sinatra differs from these systems in two important ways.…”

Lightweight Online Software Updates for C Applications

“…DSU systems for Java programs: Some dynamic update systems for Java applications expand the standard APIs provided by the Java virtual machine [9,10,11,12]. Others implement dynamic updates as an additional service of the Java virtual machine [13,14]. The former approach is easy-to-implement, but not flexible.…”

JooFlux : modification de code à chaud et injection d'aspects directement dans une JVM 7

“…Les travaux de [4] illustrent le fait que fournir une machine virtuelle modifiée est une solution permettant d'offrir un panorama complet d'opérations de modifications dynamiques d'applications Java. Ces résultats concordent avec [24].…”

“…Cette approche requiert toutefois une machine virtuelle modifiée. Les mêmes auteurs utilisent cette même machine virtuelle modifiée et appliquent une programmation par aspects dynamique dans [24]. Il est important également de mentionner que la redéfinition des classes passe par un rechargement dans la machine virtuelle.…”