selecting a subset without opening the entire file

I am using the example at
http://www.hdfgroup.org/hdf-java-html/hdf-object/javaExample/H5SubsetSelect.java.
But as far as I know, the call to testFile.open reads the entire file
structure into memory. I have a very large file and I only want to
select a subset of a dataset inside that file. Is there a way that I
can read the subset without opening the entire file?

Thank you,

Marcio