A problem with java application development

I am developing an application in Java. I have run into a roadblock in my programming... can anyone help me please. Basically the application is linked to a proprietary medical monitoring device which transmits data for anaesthesia monitoring. My Program takes this data in the form of a byte stream. It parses it according to the defined in the proprietary documentation. After parsing the data it aims to present the data in 2 different ways: - digit fields containg digit values of variables -- this is not a problem - continuous graphs of data points in the data transmitted as wave data points - this is where there appears to be a problem Without going into minute dtails the system work like this: I have 3 Time ScheduledExecutorService Threads. - scheduler thread 1: reads the data from the monitor every second and analyses, parses and extracts the data- this is not a problem - scheduler threads 2 and 3: These threads read data every few millliseconds from a class I have created that stores the data points retrieved in scheduler thread 1. The first variable being read is CO2 levels - graphing this data has not proven a problem. The second thread reads ECG data points to create an ECG trace. These 2 threads do this this by using the Observable/ Observer class . When the the Scheduler thread is activated it obtains the most recent waveform data point and notifies the Observers that the value has changed. The observer is a plotting program The CO2 trace works fine but the ECG trace stops either immediately or after a few seconds or even minutes. I worked out that this is either a thread management issue or an issue with the way I have implemented the Oberserver class for the 2 schedulers. I can see that the ECG waveform data is continually analysed and place in the appropriate variables even after the hangs. Can Anyone please assist with this problem.