Cut few segments

I need to cut a few segments from a video file and save each one an individual file.
The code below glues all the segments and stores them in a single file.

mediaComposer.addSourceFile(...);
mediaComposer.setTargetFile(...);
//...
final MediaFile mediaFile = mediaComposer.getSourceFiles().get(0);
mediaFile.addSegment(segment());
mediaComposer.start();

Reusing MediaComposer causes an error.