code: @Override
      public String getDefaultMimeType(Property binaryProperty) throws RepositoryException {
          try {
              Binary binary = binaryProperty.getBinary();
              return binary instanceof org.modeshape.jcr.api.Binary ? ((org.modeshape.jcr.api.Binary) binary)
                      .getMimeType() : DEFAULT_MIME_TYPE;
          } catch (IOException e) {
              logger.warn("Cannot determine default mime-type", e);
              return DEFAULT_MIME_TYPE;
          }
      }
docs: Returns the default mime-type of a given binary property.
  
  @param binaryProperty a non-null {@link javax.jcr.Property}
  @return a non-null String which represents the mime-type of the binary property.
  @throws javax.jcr.RepositoryException if any JCR related operation involving the binary property fail.