Module java.compiler
Package javax.lang.model.element

## Class UnknownElementException

- java.lang.Object
- - java.lang.Throwable
  - - java.lang.Exception
    - - java.lang.RuntimeException
      - - javax.lang.model.UnknownEntityException
        - - javax.lang.model.element.UnknownElementException

- All Implemented Interfaces:
    `Serializable`

      public class UnknownElementException
      extends UnknownEntityException

  Indicates that an unknown kind of element was encountered. This can occur if the language evolves and new kinds of elements are added to the `Element` hierarchy. May be thrown by an element visitor to indicate that the visitor was created for a prior version of the language.
  Since:
    1.6
  See Also:
    `ElementVisitor.visitUnknown(javax.lang.model.element.Element, P)`, Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `UnknownElementException​(Element e, Object p)` | Creates a new `UnknownElementException`.

  - ### Method Summary

    Modifier and Type | Method | Description
    --- | --- | ---
    `Object` | `getArgument()` | Returns the additional argument.
    `Element` | `getUnknownElement()` | Returns the unknown element.

    - ### Methods declared in class java.lang.Throwable

      `addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString`

    - ### Methods declared in class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### UnknownElementException

          public UnknownElementException​(Element e,
                                         Object p)

      Creates a new `UnknownElementException`. The `p` parameter may be used to pass in an additional argument with information about the context in which the unknown element was encountered; for example, the visit methods of `ElementVisitor` may pass in their additional parameter.
      Parameters:
        `e` - the unknown element, may be `null`
        `p` - an additional parameter, may be `null`

  - ### Method Detail

    - #### getUnknownElement

          public Element getUnknownElement()

      Returns the unknown element. The value may be unavailable if this exception has been serialized and then read back in.
      Returns:
        the unknown element, or `null` if unavailable

    - #### getArgument

          public Object getArgument()

      Returns the additional argument.
      Returns:
        the additional argument, or `null` if unavailable