FFT result interpretation

Question

I am developing an android app that will do human activity recognition. I am using Apache Commons to calculate my time domain features already. Now, I want to use Fast Fourier Transform method of the library to convert my time domain data (raw xyz values) from the accelerometer to the frequency domain. I am not sure how to interpret the result. Am I correct to interpret the result as a bin corresponding to each of the frequency for the values of X (for example) at each of those frequencies?

This is the code I have:

public class MyFFT {

public static void computeFFT(double[] input) {
    FastFourierTransformer transformer = new FastFourierTransformer(DftNormalization.STANDARD);
    Complex[] complexResults = transformer.transform(input, TransformType.FORWARD);

    for(Complex c:complexResults){
        System.out.println(c.getReal());
    }
    System.out.println(complexResults.toString());
}
}

And its usage:

public class main {

public static void main(String[] args) {
    double[] xValues = new double[]{0.5,1.5,1.2,0.5,0.8,1.5,1.9,2.9};

    MyFFT.computeFFT(xValues);
}
}

Output:

10.8
1.3970562748477138
-1.7999999999999998
-1.9970562748477145
-2.0
-1.9970562748477139
-1.7999999999999998
 1.3970562748477144