cdm/src/main/java/ucar/nc2/NetcdfFile.java
public void finish() {
    if (immutable) throw new IllegalStateException("Cant modify");
    variables = new ArrayList<>();
    dimensions = new ArrayList<>();
    gattributes = new ArrayList<>();
    finishGroup(rootGroup);
  }
public void finish() {
    if (immutable) throw new IllegalStateException("Cant modify");
    variables = new ArrayList<>();
    dimensions = new ArrayList<>();
    gattributes = new ArrayList<>();
    finishGroup(rootGroup);
  }
Finish constructing the object model.
This construsts the "global" variables, attributes and dimensions.
It also looks for coordinate variables.