Method Throws java.lang.NullPointerException after calling it

Question

I have a Class Sample and I call the method calcValues in my main class. But if I call calcValues, it throws a Null Pointer Exeption. But I do not know why...

Here is the code:

Class Sample:

public List<Float> calcValues(List<Float> inputValues) 
{
    List<Float> outValues = new ArrayList<>();

    for (Float value : inputValues) //causes the error
    {
        SensorDataResult res = this.mySensorData.computeAverage(value); 
        System.out.print("Ergebnis: ");
        System.out.print(res);
        if(res != null) 
        {
            // TODO Maybe check for Alarms
            outValues.add(res.getValue());
        }
    }
    return outValues;
}

Class Main:

public static void main(String[] args) 
{
    Sample newSample = new Sample();
    List<Float> inputValues = new ArrayList<Float>();
    inputValues.add(10.0f);  
    newSample.calcValues(inputValues); //causes the error in main class
}

Why does this method (calcValues) throw an error when I call it?

The StackTrace:

Exception in thread "main" java.lang.NullPointerException at at.axtesys.idr.Sample.calcValues(Sample.java:29) at at.axtesys.idr.TCPServer.main(TCPServer.java:24)