Because the program is running in a distributed way, both the concurrent features and the runtime environments should be taken into account when testing a distributed program. A Java oriented distributed program test system is put forward in this paper, which is called JDPT (Java-oriented distributed program testing system). JDPT defines events based on the runtime environments, records execution processes of the distributed program as event sequences, and defines event sequencing constraints to check the validity of those feasible set of event sequences. By the technology, the JDPT can effectively estimate the correctness of concurrent executions of the tested program within distributed environments, and can be used to test Java programs running upon multiple platforms.