code: public boolean isConvertible(final Class<?> cls) {
          try {
              return cls != null && findConverterQuiet(cls) != null;
          } catch (RuntimeException ex) {
              return false;
          }
      }
docs: Checks if a suitable converter exists for the type.
  <p>
  This performs the same checks as the {@code findConverter} methods.
  Calling this before {@code findConverter} will cache the converter.
  <p>
  Note that all exceptions, including developer errors are caught and hidden.
  
  @param cls  the class to find a converter for, null returns false
  @return true if convertible
  @since 1.5