final Path file = new Path(new File("target/test/test-camel-double").getAbsolutePath());
Configuration conf = new Configuration();
FileSystem fs1 = FileSystem.get(file.toUri(), conf);
SequenceFile.Writer writer = createWriter(fs1, conf, file, NullWritable.class, DoubleWritable.class);
NullWritable keyWritable = NullWritable.get();
DoubleWritable valueWritable = new DoubleWritable();
double value = 3.1415926535;
valueWritable.set(value);
writer.append(keyWritable, valueWritable);
writer.sync();