How do i convert matlab code into java code????

I have piece of matlab code, I am trying to convert that to java opencv code manually. But I am facing some problems while conversion, some of the functions are not available in java. So plz help me with those functions.

imj = im2double(y); r = imj(:,:,1); g = imj(:,:,2); b = imj(:,:,3);

rgbfcm=cast(o,class(y)); redPlane = y(:, :, 1).*rgbfcm; greenPlane =y(:, :, 2).*rgbfcm; bluePlane = y(:, :, 3).*rgbfcm; fcmrgb = cat(3, redPlane,greenPlane, bluePlane);

These are the functions/oprations that need to be converted to java. Plz Help me with these code.