Developers writing Android applications suffer from a dreadful redeploy time every time they need to test changes to the source code. While runtime class reloading systems are widely used for the underlying programming language, Java, there is currently no support for reloading code on the Android platform. This paper presents a new tool, JRebel.Android that enables automatic runtime class- and resource reloading capabilities for Android. The target of this paper is the Android developer as well as the researcher for which dynamic updating capabilities on mobile devices can serve as a basic building block within areas such as runtime maintenance or self-adaptive systems. JRebel.Android is able to reload classes in much less than 1 second, saving more than 91% of the total redeploy time for small apps, more than 95% for medium size apps, and even more for larger apps.Accompanying video: https://www.youtube.com/watch?v=bpVwKcvNQEs

Any non-trivial software system has to be upgraded regularly to incorporate bug fixes and security patches or simply to keep up with the inevitable evolution in end-user requirements. Software upgrading is challenging, especially when it comes to online upgrading of running systems. In this paper, we present the current status of Gosh!, a dynamic-software-updating system for Java, which provides comprehensive support for changing class definitions of live objects, including adding, removing and moving fields, methods, classes and interfaces anywhere in the inheritance hierarchy. Prior to the acquisition by zeroturnaround.com, Gosh! was known as Javeleon. In this paper we demonstrate the capabilities of Gosh! by performing a dynamic updating experiment on five consecutive revisions of the classical arcade game Breakout. Based on the result of this experiment we show that dynamic updating of class definitions for live objects may under some circumstances result in different run-time behavior than would be observed after a cold restart of the upgraded application. Finally, we conclude by discussing the implication of this finding for future research directions within dynamic software updating.

Many kinds of software systems benefit from the capability to modify a system's design decisions at run-time. In this paper, design patterns are proposed as the basic elements of dynamic design-level maintenance. The required infrastructure for pattern-based dynamic system maintenance has been implemented for Java. The infrastructure provides a graphical presentation of the system's pattern architecture, and supports injecting and disposing of patterns in a running system. The potential benefits of the approach are demonstrated with an example system.

Abstract The ability to dynamically change the behavior of an application is becoming an important issue in contemporary rich client software development. Not only can programmers benefit from dynamic updates during the development of concurrent applications where recreation of complex application states can be avoided during test and debugging but also at post‐deployment time where applications can be updated transparently without going through the well‐known halt, redeploy and restart scheme. In this paper, we explain how our dynamic update framework achieves transparent dynamic updates of running Java applications while guaranteeing both type and thread safety. A novel feature of our approach is that it supports full redefinition of classes by allowing changes to the type hierarchy. Our approach is based on a lightweight runtime system, which is injected into an application via bytecode transformations at class loading. We show how our approach can add dynamic update capabilities to rich client development by integrating it with the NetBeans rich client platform. Performance experiments on our NetBeans implementation show that the overhead of our approach is low when applied to component application programming interface classes. To the best of our knowledge no other existing approach achieves the same level of low overhead and programming transparency. Copyright © 2009 John Wiley & Sons, Ltd.