#vulnerable code 
                                @Override
    protected void process(ComplexEventChunk<StreamEvent> streamEventChunk, Processor nextProcessor, StreamEventCloner streamEventCloner, ComplexEventPopulater complexEventPopulater) {
        while (streamEventChunk.hasNext()) {
            ComplexEvent complexEvent = streamEventChunk.next();

            Object[] inputData = new Object[attributeExpressionLength-paramPosition];
            double xDash = ((Number) attributeExpressionExecutors[paramPosition-1].execute(complexEvent)).doubleValue();
            for (int i = paramPosition; i < attributeExpressionLength; i++) {
                inputData[i-paramPosition] = attributeExpressionExecutors[i].execute(complexEvent);
            }
            Object[] temp = regressionCalculator.calculateLinearRegression(inputData);
            Object[] outputData = new Object[temp.length+1];
            System.arraycopy(temp, 0, outputData, 0, temp.length);
            outputData[temp.length] = ((Number) temp[temp.length-2]).doubleValue() + ((Number) temp[temp.length-1]).doubleValue() * xDash;


            if (outputData == null) {
                streamEventChunk.remove();
            } else {
                complexEventPopulater.populateComplexEvent(complexEvent, outputData);
            }
        }
        nextProcessor.process(streamEventChunk);
    } 
                            #location 12 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    protected void process(ComplexEventChunk<StreamEvent> streamEventChunk, Processor nextProcessor, StreamEventCloner streamEventCloner, ComplexEventPopulater complexEventPopulater) {
        while (streamEventChunk.hasNext()) {
            ComplexEvent complexEvent = streamEventChunk.next();

            Object[] inputData = new Object[attributeExpressionLength-paramPosition];

            // Obtain x value that user wants to use to forecast Y
            double xDash = ((Number) attributeExpressionExecutors[paramPosition-1].execute(complexEvent)).doubleValue();
            for (int i = paramPosition; i < attributeExpressionLength; i++) {
                inputData[i-paramPosition] = attributeExpressionExecutors[i].execute(complexEvent);
            }
            Object[] coefficients = regressionCalculator.calculateLinearRegression(inputData);

            if (coefficients == null) {
                streamEventChunk.remove();
            } else {
                Object[] outputData = new Object[coefficients.length+1];
                System.arraycopy(coefficients, 0, outputData, 0, coefficients.length);

                // Calculating forecast Y based on regression equation and given x
                outputData[coefficients.length] = ((Number) coefficients[coefficients.length-2]).doubleValue() + ((Number) coefficients[coefficients.length-1]).doubleValue() * xDash;
                complexEventPopulater.populateComplexEvent(complexEvent, outputData);
            }
        }
        nextProcessor.process(streamEventChunk);
    }