# Package net.corda.core.utilities

- Class Summary
  Class | Description
  --- | ---
  ApiUtils | Utility functions to reduce boilerplate when developing HTTP APIs
  Emoji | A simple wrapper class that contains icons and support for printing them only when we're connected to a terminal.
  LogHelper | A configuration helper that allows modifying the log level for specific loggers
  LoggingKt |
  NonEmptySet<T> | A set which is constrained to ensure it can never be empty. An initial value must be provided at construction, and attempting to remove the last element will cause an IllegalStateException. The underlying set is exposed for Kryo to access, but should not be accessed directly.
  NonEmptySetKt |
  NonEmptySetSerializer | Custom serializer which understands it has to read in an item before trying to construct the set.
  ProgressTracker | A progress tracker helps surface information about the progress of an operation to a user interface or API of some kind. It lets you define a set of steps that represent an operation. A step is represented by an object (typically a singleton).
  TestConstants |
  TimeWindow | A class representing a window in time from a particular instant, lasting a specified duration.
  UntrustworthyData<T> | A small utility to approximate taint tracking: if a method gives you back one of these, it means the data came from a remote source that may be incentivised to pass us junk that violates basic assumptions and thus must be checked first. The wrapper helps you to avoid forgetting this vital step. Things you might want to check are:
  UntrustworthyDataKt |