Hadoop constructing public instance variables?

[Ted Dziuba <tj...@gmail.com>]

Hello all,

I have my own VersionedWritable class like so:


public class MyWritable extends VersionedWritable {
  
  public OtherWritable anotherWritable; // instance var, implements Writable
  ...

  public MyWritable() {
    anotherWritable = null;
  }

  @Override
  public void readFields(DataInput in) {
    if (condition) {
      anotherWritable = new OtherWritable();
      // ...
    }
  }
}


I can verify that the no-arg constructor of MyWritable is being called,
but it appears as if the no-arg constructor for OtherWritable is being
called some time between the construction of MyWritable and the call to
MyWritable's readFields().  Is this expected behavior, because the
OtherWritable is a public instance variable that implements Writable?

This is happening when a SequenceFile containing a bunch of these is
read into a Reducer.

Ted