In JForex a strategy is not necessarily coupled with a chart - one strategy might work with multiple charts and in many cases it works with none. From a stratetgy charts are used to plot chart objects and indicators. You can retrieve a chart for a specific instrument by using
IContext.getChart(instrument) and all charts for the instrument by
IContext.getCharts(instrument). Find more here:
https://www.dukascopy.com/wiki/index.php?title=IChart