MonitorInfo (Java Platform SE 8 )
Keywords: java.lang.management.MonitorInfo class
Date: 2026-04-17

compact3
java.lang.management

## Class MonitorInfo

- java.lang.Object
- - java.lang.management.LockInfo
  - - java.lang.management.MonitorInfo

-     public class MonitorInfo
      extends LockInfo

  Information about an object monitor lock. An object monitor is locked when entering a synchronization block or method on that object.

  ### MXBean Mapping

  `MonitorInfo` is mapped to a `CompositeData` with attributes as specified in the `from` method.
  Since:
    1.6

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `MonitorInfo(String className, int identityHashCode, int stackDepth, StackTraceElement stackFrame)` Construct a `MonitorInfo` object.

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `static MonitorInfo` | `from(CompositeData cd)` Returns a `MonitorInfo` object represented by the given `CompositeData`.
    `int` | `getLockedStackDepth()` Returns the depth in the stack trace where the object monitor was locked.
    `StackTraceElement` | `getLockedStackFrame()` Returns the stack frame that locked the object monitor.

    - ### Methods inherited from class java.lang.management.LockInfo

      `getClassName, getIdentityHashCode, toString`

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### MonitorInfo

          public MonitorInfo(String className,
                             int identityHashCode,
                             int stackDepth,
                             StackTraceElement stackFrame)

      Construct a `MonitorInfo` object.
      Parameters:
        `className` - the fully qualified name of the class of the lock object.
        `identityHashCode` - the `identity hash code` of the lock object.
        `stackDepth` - the depth in the stack trace where the object monitor was locked.
        `stackFrame` - the stack frame that locked the object monitor.
      Throws:
        `IllegalArgumentException` - if `stackDepth` ≥ 0 but `stackFrame` is `null`, or `stackDepth` < 0 but `stackFrame` is not `null`.

  - ### Method Detail

    - #### getLockedStackDepth

          public int getLockedStackDepth()

      Returns the depth in the stack trace where the object monitor was locked. The depth is the index to the `StackTraceElement` array returned in the `ThreadInfo.getStackTrace()` method.
      Returns:
        the depth in the stack trace where the object monitor was locked, or a negative number if not available.

    - #### getLockedStackFrame

          public StackTraceElement getLockedStackFrame()

      Returns the stack frame that locked the object monitor.
      Returns:
        `StackTraceElement` that locked the object monitor, or `null` if not available.

    - #### from

          public static MonitorInfo from(CompositeData cd)

      Returns a `MonitorInfo` object represented by the given `CompositeData`. The given `CompositeData` must contain the following attributes as well as the attributes specified in the mapped type for the `LockInfo` class:

      > Attribute Name | Type
      > --- | ---
      > lockedStackFrame | `CompositeData as specified in the stackTrace attribute defined in the `ThreadInfo.from` method.`
      > lockedStackDepth | `java.lang.Integer`

      Parameters:
        `cd` - `CompositeData` representing a `MonitorInfo`
      Returns:
        a `MonitorInfo` object represented by `cd` if `cd` is not `null`; `null` otherwise.
      Throws:
        `IllegalArgumentException` - if `cd` does not represent a `MonitorInfo` with the attributes described above.

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