using SIFT/SURF for feature extraction using opencv on android using Android App?

I'm working on a feature extraction/matching app using opencv on android . I'm trying to use those lines in my android app but the app crash even if the variables featureDetector & descriptorExtractor are not NULL. FeatureDetector featureDetector = FeatureDetector.create(FeatureDetector.SIFT); DescriptorExtractor descriptorExtractor = DescriptorExtractor.create(DescriptorExtractor.SIFT); it crashes exactly when I call this line featureDetector.detect(image,matOfKeyPoint);