Dynamic class loading in the Java virtual machine

Abstract. Replacing or adding network protocols at runtime is problematic -it must involve synchronization of the protocol switch with ongoing local and network communication. We define a formal mathematical model of dynamic protocol update (DPU) and use it to define two DPU algorithms. The algorithms are based on fully-synchronized and lazy strategies. The two strategies implement updates with respectively, strong and weak safety properties. Our model allowed us to express the properties and the DPU algorithms clearly and abstractly, aiding algorithm design and correctness proofs.

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“…[4,1,6,9]). Software components can be rebound on-the-fly, using a mechanism of dynamic class loading and linking [10,15].…”

Section: Introductionmentioning

confidence: 99%

On Correctness of Dynamic Protocol Update

Wojciechowski

Rütti

2005

Lecture Notes in Computer Science

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“…Recall that a Java class type is uniquely determined by the combination of a class loader and a fully qualified class name [18]. In response to changes in the deployment directory, JBoss instantiates class loaders to dynamically define new class types, which may correspond to "new versions" of previously defined class types.…”

Section: Deployment and Undeploymentmentioning

confidence: 99%

“…Components loaded from different deployment units may contain classes with the same name, but these classes will be treated as different types by the Java virtual machine [18]. This approach avoids class clashes between deployment units, but hinders interactions between separately deployed parts.…”

Section: Class Loading Issuesmentioning

confidence: 99%

The JBoss Extensible Server

Fleury¹,

Reverbel

2003

Lecture Notes in Computer Science

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Abstract. JBoss is an extensible, reflective, and dynamically reconfigurable Java application server. It includes a set of components that implement the J2EE specification, but its scope goes well beyond J2EE. JBoss is open-ended middleware, in the sense that users can extend middleware services by dynamically deploying new components into a running server. We believe that no other application server currently offers such a degree of extensibility. This paper focuses on two major architectural parts of JBoss: its middleware component model, based on the JMX model, and its meta-level architecture for generalized EJBs. The former requires a novel class loading model, which JBoss implements. The latter includes a powerful and flexible remote method invocation model, based on dynamic proxies, and relies on systematic usage of interceptors as aspect-oriented programming artifacts.

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“…Or how can an application determine whether the module to be retrieved is already loaded and initialized or not? The first question is targeting a basic problem of the original class loader approach of Java which does not allow loading two classes having the same fully-qualified class name (FQCN) by the same class loader [25]. Thus, in order to support the composition of modules in different variants within the same JVM, we have to use and manage several class loaders.…”

Section: Fig 8 Module Deployment Using Class Collectionsmentioning

confidence: 99%

Separating the Concerns of Distributed Deployment and Dynamic Composition in Internet Application Systems

Paal

Kammüller

Freisleben

2003

On the Move to Meaningful Internet Systems 2003: CoopIS, DOA, and ODBASE

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Abstract. The Internet is currently evolving from a global information network into a distributed application system. For example, some Internet applications are based on executing remote services which have been previously installed on possibly multiple Internet nodes, whereas parts of other Internet applications are dynamically moved from several remote nodes to be executed on a single node. In this paper, we focus on the related problem of how the parts of an Internet application that have been independently deployed on multiple Internet nodes can be transparently located, seamlessly retrieved and dynamically composed on a particular node by request. We propose a novel deployment and composition approach using so called modules and module federations and show how to separate the logical application composition from the physical module deployment. The realization of our proposal in Java and C++ is presented and the use of the approach in ongoing research projects is demonstrated.

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Dynamic class loading in the Java virtual machine

Cited by 104 publications

References 7 publications

On Correctness of Dynamic Protocol Update

On Correctness of Dynamic Protocol Update

The JBoss Extensible Server

Separating the Concerns of Distributed Deployment and Dynamic Composition in Internet Application Systems

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