A Dynamic Logic for Deductive Verification of Concurrent Programs Bernhard Beckert and Vladimir Klebanov In this paper, we present an approach aiming at full functional deductive verification of concurrent Java programs, based on symbolic execution. We define a Dynamic Logic and a deductive verification calculus for a restricted fragment of Java with native concurrency primitives. Even though we cannot yet deal with non-atomic loops, employing the technique of symmetry reduction allows us to verify unbounded systems. The calculus has been implemented within the KeY system, and we demonstrate it by verifying a central method of the StringBuffer class from the Java standard library.