Class VMOption

public class VMOption
extends Object

Information about a VM option including its value and where the value came from which is referred as its origin.

Each VM option has a default value. A VM option can be set at VM creation time typically as a command line argument to the launcher or an argument passed to the VM created using the JNI invocation interface. In addition, a VM option may be set via an environment variable or a configuration file. A VM option can also be set dynamically via a management interface after the VM was started. A VMOption contains the value of a VM option and the origin of that value at the time this VMOption object was constructed. The value of the VM option may be changed after the VMOption object was constructed,

Since:
1.6

Nested Classes

Modifier and Type Class Description
static class  VMOption.Origin

Origin of the value of a VM option.

Constructors

Constructor Description
VMOption​(String name, String value, boolean writeable, VMOption.Origin origin)

Constructs a VMOption.

Methods

Modifier and Type Method Description
static VMOption from​(CompositeData cd)

Returns a VMOption object represented by the given CompositeData.
String getName()

Returns the name of this VM option.
VMOption.Origin getOrigin()

Returns the origin of the value of this VM option.
String getValue()

Returns the value of this VM option at the time when this VMOption was created.
boolean isWriteable()

Tests if this VM option is writeable.

Methods declared in class java.lang.Object

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

Constructors

VMOption

public VMOption(String name,
                String value,
                boolean writeable,
                VMOption.Origin origin)

Constructs a VMOption.

Parameters:
name - Name of a VM option.
value - Value of a VM option.
writeable - true if a VM option can be set dynamically, or false otherwise.
origin - where the value of a VM option came from.
Throws:
NullPointerException - if the name or value is null

Methods

getName

public String getName()

Returns the name of this VM option.

Returns:
the name of this VM option.

getValue

public String getValue()

Returns the value of this VM option at the time when this VMOption was created. The value could have been changed.

Returns:
the value of the VM option at the time when this VMOption was created.

getOrigin

public VMOption.Origin getOrigin()

Returns the origin of the value of this VM option. That is, where the value of this VM option came from.

Returns:
where the value of this VM option came from.

isWriteable

public boolean isWriteable()

Tests if this VM option is writeable. If this VM option is writeable, it can be set by the HotSpotDiagnosticMXBean.setVMOption method.

Returns:
true if this VM option is writeable; false otherwise.

from

public static VMOption from(CompositeData cd)

Returns a VMOption object represented by the given CompositeData. The given CompositeData must contain the following attributes:

Attribute Name Type
name java.lang.String
value java.lang.String
origin java.lang.String
writeable java.lang.Boolean

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