Campus Event Calendar

Event Entry

What and Who

From Replication to Flexible and Portable Determinism for Java

Joerg Domaschka
Institute for Information Resource Management, Ulm University
SWS Colloquium

Jörg Domaschka received a diploma in computer science from the university of Erlangen-Nuremberg, Germany in 2005. From 2006 to 2012,
he was an assistant researcher in Franz Hauk's research group at the Institute for Distributed Systems, University of Ulm, Germany.
From 2012 to 2013 he worked as a business consultant. He received a doctor degree from the University of Ulm in 2013; in May 2013 he
returned to academia and joined Stefan Wesner's Institute for Information Resource Management at University of Ulm as a senior researcher.
In the past, Jörg's research activity was mainly concerned with distributed, fault-tolerant systems and the automatic provisioning of fault-tolerance
and determinism. His interests, however, also cover distributed algorithms, self-adaptability, scalability, as well as programming paradigms for such
systems. In the past, he actively participated in the XtreemOS FP6 project where he technically led the group of Univeristy of Ulm. Further, he
functioned as a key developer in the project. He is now contributing to the PaaSage FP7 project and will soon start working on the FP7 project CACTOS.
AG Audience

Date, Time and Location

Monday, 5 August 2013
90 Minutes
E1 5


Determinism of applications is required in the domains of testing, debugging, and fault-tolerant replication. Literature has presented various ways to render application execution deterministic in either transparent or non-transparent manner. Existing approaches operate on the layers of hardware, operating system, rutime environments, or even inside the application logic. Other systems operate in-between two layers: hypervisors between hardware and operating system; and supervisors between operating systems and applications.
In this talk, I focus on the combination of replication and determinism: Applying replication techniques and replication protocols to business applications requires that the logic of the business application behave deterministic, while the other parts of the system such as the replication logic does not.
This talk gives a brief introduction to the Java-based Virtual Nodes Replication Framework (VNF). VNF allows a transparent replication of business logic. It enables a late configuration of multiple aspects of a replica group including the particular replication protocol. Deciding late which replication protocol to apply, however, is only possible when the application logic satisfies contraints imposed by the replication protocol. Many replication protocols can only be applied when it is ensured that the application logic behaves deterministically.
The Deterministic Java suite (Dj suite) is capable of rendering Java applications fully deterministic. In contrast to other approaches, it is pure Java and hence, portable across JVMs, operating systems, and hardware platforms. Furthermore, it can be selectively applied to only parts of entire Java programmes what makes it suited for replicated scenarios. In addition, the Dj suite comprises a deterministic version of the Java runtime libraries which makes it the only comprehensive, Java-based approach in literature. The capability for a flexible configuration ensures adaptability to many different use cases.
In this talk, I give an overview on mechanisms and techniques for making Java applications deterministic. In addition, I sketch how to build a determinitic Java-only runtime system from an existing open source Java implementation. The talk concludes with evaluation results, a discussion of future work, and an outlook on the integration of Dj with VNF as well as the possibility of virtualised Java platforms.


Claudia Richter
9303 9103
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Brigitta Hansen, 08/22/2013 10:48
Claudia Richter, 08/05/2013 11:47 -- Created document.