Class VirtualMachineDescriptor

public class VirtualMachineDescriptor
extends Object

Describes a Java virtual machine.

A VirtualMachineDescriptor is a container class used to describe a Java virtual machine. It encapsulates an identifier that identifies a target virtual machine, and a reference to the AttachProvider that should be used when attempting to attach to the virtual machine. The identifier is implementation-dependent but is typically the process identifier (or pid) environments where each Java virtual machine runs in its own operating system process.

A VirtualMachineDescriptor also has a displayName. The display name is typically a human readable string that a tool might display to a user. For example, a tool that shows a list of Java virtual machines running on a system might use the display name rather than the identifier. A VirtualMachineDescriptor may be created without a display name. In that case the identifier is used as the display name.

VirtualMachineDescriptor instances are typically created by invoking the VirtualMachine.list() method. This returns the complete list of descriptors to describe the Java virtual machines known to all installed attach providers.

Since:
1.6

Constructors

Constructor Description
VirtualMachineDescriptor​(AttachProvider provider, String id)

Creates a virtual machine descriptor from the given components.
VirtualMachineDescriptor​(AttachProvider provider, String id, String displayName)

Creates a virtual machine descriptor from the given components.

Methods

Modifier and Type Method Description
String displayName()

Return the display name component of this descriptor.
boolean equals​(Object ob)

Tests this VirtualMachineDescriptor for equality with another object.
int hashCode()

Returns a hash-code value for this VirtualMachineDescriptor.
String id()

Return the identifier component of this descriptor.
AttachProvider provider()

Return the AttachProvider that this descriptor references.
String toString()

Returns the string representation of the VirtualMachineDescriptor.

Methods declared in class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructors

VirtualMachineDescriptor

public VirtualMachineDescriptor(AttachProvider provider,
                                String id,
                                String displayName)

Creates a virtual machine descriptor from the given components.

Parameters:
provider - The AttachProvider to attach to the Java virtual machine.
id - The virtual machine identifier.
displayName - The display name.
Throws:
NullPointerException - If any of the arguments are null

VirtualMachineDescriptor

public VirtualMachineDescriptor(AttachProvider provider,
                                String id)

Creates a virtual machine descriptor from the given components.

This convenience constructor works as if by invoking the three-argument constructor as follows: 

new VirtualMachineDescriptor(provider,  id,  id);

That is, it creates a virtual machine descriptor such that the display name is the same as the virtual machine identifier.

Parameters:
provider - The AttachProvider to attach to the Java virtual machine.
id - The virtual machine identifier.
Throws:
NullPointerException - If provider or id is null.

Methods

provider

public AttachProvider provider()

Return the AttachProvider that this descriptor references.

Returns:
The AttachProvider that this descriptor references.

id

public String id()

Return the identifier component of this descriptor.

Returns:
The identifier component of this descriptor.

displayName

public String displayName()

Return the display name component of this descriptor.

Returns:
The display name component of this descriptor.

hashCode

public int hashCode()

Returns a hash-code value for this VirtualMachineDescriptor. The hash code is based upon the descriptor's components, and satifies the general contract of the Object.hashCode method.

Overrides:
hashCode in class Object
Returns:
A hash-code value for this descriptor.
See Also:
Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

equals

public boolean equals(Object ob)

Tests this VirtualMachineDescriptor for equality with another object.

If the given object is not a VirtualMachineDescriptor then this method returns false. For two VirtualMachineDescriptors to be considered equal requires that they both reference the same provider, and their identifiers are equal.

This method satisfies the general contract of the Object.equals method.

Overrides:
equals in class Object
Parameters:
ob - The object to which this object is to be compared
Returns:
true if, and only if, the given object is a VirtualMachineDescriptor that is equal to this VirtualMachineDescriptor.
See Also:
Object.hashCode(), HashMap

toString

public String toString()

Returns the string representation of the VirtualMachineDescriptor.

Overrides:
toString in class Object
Returns:
a string representation of the object.

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
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https://docs.oracle.com/en/java/javase/11/docs/api/jdk.attach/com/sun/tools/attach/VirtualMachineDescriptor.html