code: public static final PackageBuilder findPackageBuilder(String name)
      {
          Objects.requireNonNull(name, "name cannot be null");
          ServiceLoader<PackageBuilderProvider> loader = ServiceLoader.load(PackageBuilderProvider.class);
          Iterator<PackageBuilderProvider> iterator = loader.iterator();
          while (iterator.hasNext())
          {
              PackageBuilderProvider pbp = iterator.next();
              if (name.equals(pbp.getPackageBuilderName()))
              {
                  Mapper.setKey(name);
                  return pbp.newInstance();
              }
          }
          throw new UnsupportedOperationException("package builder "+name+" not found");
      }
docs: Returns PackageBuilder for name. It also sets Mapper key to that name.
  <p>
  Currently supported are "rpm" and "deb". It is possible to create new
  builders by providing PackageBuilderProvider implementation class in file
  META-INF/services/org.vesalainen.pm.PackageBuilderProvider
  @param name
  @return
  @see java.util.ServiceLoader