On Sep 25, 2017, at 9:34 AM, Mr Huanfa Chen <[log in to unmask]> wrote:

> The problem is in the line of "trafficChart.removeAllSeries();". I guess the TimeSeriesChartGenerator object is not correctly constructed.

I can't look into it immediately, but if it's a null pointer exception, then it means that the trafficChart variable is null at that point.  Perhaps it had not yet been built?

Sean