# Uses of Class
jdk.jfr.MetadataDefinition

Packages that use MetadataDefinition
Package | Description
--- | ---
jdk.jfr | This package provides classes to create events and control Flight Recorder.

## Uses of MetadataDefinition in jdk.jfr

Classes in jdk.jfr with annotations of type MetadataDefinition
Modifier and Type | Class | Description
--- | --- | ---
`interface` | `BooleanFlag` | Event field annotation, specifies that the value is a boolean flag, a `true` or `false` value
`interface` | `Category` | Event annotation, to associate the event type with a category, in the format of a human-readable path.
`interface` | `ContentType` | Meta annotation, specifies that an annotation represents a content type, such as a time span or a frequency.
`interface` | `DataAmount` | Event field annotation, specifies that a value represents an amount of data (for example, bytes).
`interface` | `Description` | Annotation that describes an element by using a sentence or two.
`interface` | `Enabled` | Event annotation, determines if an event should be enabled by default.
`interface` | `Experimental` | Annotation that specifies that an element is experimental and may change without notice.
`interface` | `Frequency` | Event field annotation, specifies that the value is a frequency, measured in Hz.
`interface` | `Label` | Annotation that sets a human-readable name for an element (for example, `"Maximum Throughput"`).
`interface` | `MemoryAddress` | Event field annotation, specifies that the value is a memory address.
`interface` | `Name` | Annotation that overrides the default name for an element (for example, when the default package for an event is not appropriate).
`interface` | `Percentage` | Event field annotation to use on fractions, typically between `0.0` and `1.0`, to specify that the value is a percentage.
`interface` | `Period` | Event annotation, specifies the default setting value for a periodic event.
`interface` | `Relational` | Meta annotation for relational annotations, to be used on an annotation.
`class` | `SettingControl` | Base class to extend to create setting controls.
`interface` | `StackTrace` | Event annotation, determines whether an event by default has a stack trace or not.
`interface` | `Threshold` | Event annotation, specifies the default duration below which an event is not recorded (for example, `"20 ms"`).
`interface` | `Timespan` | Event field annotation, specifies that the value is a duration.
`interface` | `Timestamp` | Event field annotation, specifies that the value is a point in time.
`interface` | `TransitionFrom` | Event field annotation, specifies that the event transitioned from a thread.
`interface` | `TransitionTo` | Event field annotation, specifies that the event will soon transition to a thread.
`interface` | `Unsigned` | Event field annotation, specifies that the value is of an unsigned data type.