# Package nxt.util

- Interface Summary
  Interface | Description
  --- | ---
  Filter<T> |
  Listener<T> |
  Observable<T,E extends java.lang.Enum<E>> |
  ReadWriteUpdateLock.Lock | Lock interface
  Time |

- Class Summary
  Class | Description
  --- | ---
  BooleanExpression | A boolean expression in disjunctive normal form - i.e.
  BooleanExpression.SemanticWarning |
  BriefLogFormatter | A Java logging formatter that writes more compact output than the default
  Convert |
  CountingInputReader | CountingInputReader extends Reader to count the number of characters read
  CountingOutputWriter | CountingOutputWriter extends Writer to count the number of characters written
  JSON |
  Listeners<T,E extends java.lang.Enum<E>> |
  Logger | Handle logging for the Nxt node server
  MemoryHandler | MemoryHandler maintains a ring buffer of log messages.
  MultipartUtility |
  NxtLogManager | Java LogManager extension for use with Nxt
  QueuedThreadPool | QueuedThreadPool creates threads to process requests until the maximum pool size is reached.
  ReadWriteUpdateLock | A read or update lock allows shared access while a write lock enforces exclusive access.
  ReproducibleJarOutputStream | Produce a Jar that given the same class files and timestamps, generates the binary Jar file Use this to generate test data which won't change
  ResourceLookup |
  Search |
  ThreadPool |
  Time.ConstantTime |
  Time.CounterTime |
  Time.EpochTime |
  Time.FasterTime |
  TrustAllSSLProvider |
  UPnP | Forward ports using the UPnP protocol.

- Enum Summary
  Enum | Description
  --- | ---
  BooleanExpression.SemanticWarningType |
  BooleanExpression.SyntaxError |
  BooleanExpression.Value |
  Logger.Event | Log event types
  Logger.Level | Log levels

- Exception Summary
  Exception | Description
  --- | ---
  BooleanExpression.BadSyntaxException |
  BooleanExpression.BooleanExpressionException |