Constitutes the refereed proceedings of the 9th IFIP WG 6.1 International Conference on Formal Methods for Open Object-Based Distributed Systems, FMOODS 2007, held in Paphos, Cyprus in June 2007. This title presents 17 revised full papers together with 2 invited papers that were reviewed and selected from 45 submissions.

Invited Talks.- Asynchronous Session Types and Progress for Object Oriented Languages.- KeY: A Formal Method for Object-Oriented Systems.- Model Checking.- Verifying Distributed, Event-Based Middleware Applications Using Domain-Specific Software Model Checking.- Model Checking of Extended OCL Constraints on UML Models in SOCLe.- Analysis of UML Activities Using Dynamic Meta Modeling.- Rewriting Logic.- Distributed Applications Implemented in Maude with Parameterized Skeletons.- On Formal Analysis of OO Languages Using Rewriting Logic: Designing for Performance.- Formal Modeling and Analysis of the OGDC Wireless Sensor Network Algorithm in Real-Time Maude.- Components and Services.- Adaptation of Open Component-Based Systems.- A Representation-Independent Behavioral Semantics for Object-Oriented Components.- A Formal Language for Electronic Contracts.- Algebraic Calculi.- A Mechanized Model of the Theory of Objects.- Pict Correctness Revisited.- Specification, Verfication and Refinenment.- A Refinement Method for Java Programs.- Refactoring Object-Oriented Specifications with Data and Processes.- A Sound and Complete Shared-Variable Concurrency Model for Multi-threaded Java Programs.- Quality of Service.- Performance-Oriented Comparison of Web Services Via Client-Specific Testing Preorders.- A Probabilistic Formal Analysis Approach to Cross Layer Optimization in Distributed Embedded Systems.- On Resource-Sensitive Timed Component Connectors.