https://openjdk.java.net/ 
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package com.sun.jdi;

import com.sun.jdi.event.EventQueue;
import com.sun.jdi.request.EventRequestManager;

import java.util.List;
import java.util.Map;


A virtual machine targeted for debugging. More precisely, a mirror representing the composite state of the target VM. All other mirrors are associated with an instance of this interface. Access to all other mirrors is achieved directly or indirectly through an instance of this interface. Access to global VM properties and control of VM execution are supported directly by this interface. 
 Instances of this interface are created by instances of Connector. For example, an AttachingConnector attaches to a target VM and returns its virtual machine mirror. A Connector will typically create a VirtualMachine by invoking the VirtualMachineManager's VirtualMachineManager.createVirtualMachine(Connection) createVirtualMachine(Connection) method. 
 Note that a target VM launched by a launching connector is not guaranteed to be stable until after the VMStartEvent has been received. 

Any method on VirtualMachine which
takes VirtualMachine as an parameter may throw VMDisconnectedException if the target VM is disconnected and the VMDisconnectEvent has been or is available to be read from the EventQueue. 

Any method on VirtualMachine which
takes VirtualMachine as an parameter may throw VMOutOfMemoryException if the target VM has run out of memory. 
Author:Robert Field, Gordon Hirsch, James McIlree
Since: 1.3
/**
 * A virtual machine targeted for debugging.
 * More precisely, a {@link Mirror mirror} representing the
 * composite state of the target VM.
 * All other mirrors are associated with an instance of this
 * interface.  Access to all other mirrors is achieved
 * directly or indirectly through an instance of this
 * interface.
 * Access to global VM properties and control of VM execution
 * are supported directly by this interface.
 * <P>
 * Instances of this interface are created by instances of
 * {@link com.sun.jdi.connect.Connector}. For example,
 * an {@link com.sun.jdi.connect.AttachingConnector AttachingConnector}
 * attaches to a target VM and returns its virtual machine mirror.
 * A Connector will typically create a VirtualMachine by invoking
 * the VirtualMachineManager's {@link
 * com.sun.jdi.VirtualMachineManager#createVirtualMachine(Connection)}
 * createVirtualMachine(Connection) method.
 * <p>
 * Note that a target VM launched by a launching connector is not
 * guaranteed to be stable until after the {@link com.sun.jdi.event.VMStartEvent} has been
 * received.
 * <p>
 * Any method on <code>VirtualMachine</code> which
 * takes <code>VirtualMachine</code> as an parameter may throw
 * {@link com.sun.jdi.VMDisconnectedException} if the target VM is
 * disconnected and the {@link com.sun.jdi.event.VMDisconnectEvent} has been or is
 * available to be read from the {@link com.sun.jdi.event.EventQueue}.
 * <p>
 * Any method on <code>VirtualMachine</code> which
 * takes <code>VirtualMachine</code> as an parameter may throw
 * {@link com.sun.jdi.VMOutOfMemoryException} if the target VM has run out of memory.
 *
 * @author Robert Field
 * @author Gordon Hirsch
 * @author James McIlree
 * @since  1.3
 */
public interface VirtualMachine extends Mirror {

    
Returns the loaded reference types that match a given name. The name must be fully qualified (for example, java.lang.String). The returned list will contain a ReferenceType for each class or interface found with the given name. The search is confined to loaded classes only; no attempt is made to load a class of the given name. 

The returned list will include reference types
loaded at least to the point of preparation and
types (like array) for which preparation is
not defined.

Params:
  • className – the class/interface name to search for
Returns:a list of ReferenceType objects, each mirroring a type in the target VM with the given name.
/**
     * Returns the loaded reference types that
     * match a given name. The name must be fully qualified
     * (for example, java.lang.String). The returned list
     * will contain a {@link ReferenceType} for each class
     * or interface found with the given name. The search
     * is confined to loaded classes only; no attempt is made
     * to load a class of the given name.
     * <P>
     * The returned list will include reference types
     * loaded at least to the point of preparation and
     * types (like array) for which preparation is
     * not defined.
     *
     * @param className the class/interface name to search for
     * @return a list of {@link ReferenceType} objects, each
     * mirroring a type in the target VM with the given name.
     */
    List<ReferenceType> classesByName(String className);

    
Returns all loaded types. For each loaded type in the target VM a ReferenceType will be placed in the returned list. The list will include ReferenceTypes which mirror classes, interfaces, and array types. 

The returned list will include reference types
loaded at least to the point of preparation and
types (like array) for which preparation is
not defined.

Returns:a list of ReferenceType objects, each mirroring a loaded type in the target VM.
/**
     * Returns all loaded types. For each loaded type in the target
     * VM a {@link ReferenceType} will be placed in the returned list.
     * The list will include ReferenceTypes which mirror classes,
     * interfaces, and array types.
     * <P>
     * The returned list will include reference types
     * loaded at least to the point of preparation and
     * types (like array) for which preparation is
     * not defined.
     *
     * @return a list of {@link ReferenceType} objects, each mirroring
     * a loaded type in the target VM.
     */
    List<ReferenceType> allClasses();

    
All classes given are redefined according to the
definitions supplied.  A method in a redefined class
is called 'equivalent' (to the old version of the
method) if

    

  • their bytecodes are the same except for indicies into
  the constant pool, and

  • the referenced constants are equal.

 Otherwise, the new method is called 'non-equivalent'. If a redefined method has active stack frames, those active frames continue to run the bytecodes of the previous version of the method. If the new version of such a method is non-equivalent, then a method from one of these active frames is called 'obsolete' and Method.isObsolete() will return true when called on one of these methods. If resetting such a frame is desired, use ThreadReference.popFrames(StackFrame) to pop the old obsolete method execution from the stack. New invocations of redefined methods will always invoke the new versions. 

This function does not cause any initialization except
that which would occur under the customary JVM semantics.
In other words, redefining a class does not cause
its initializers to be run. The values of preexisting
static variables will remain as they were prior to the
call. However, completely uninitialized (new) static
variables will be assigned their default value.


If a redefined class has instances then all those
instances will have the fields defined by the redefined
class at the completion of the call. Preexisting fields
will retain their previous values. Any new fields will
have their default values; no instance initializers or
constructors are run.


Threads need not be suspended.


No events are generated by this function.


All breakpoints in the redefined classes are deleted.

 Not all target virtual machines support this operation. Use canRedefineClasses() to determine if the operation is supported. Use canAddMethod() to determine if the redefinition can add methods. Use canUnrestrictedlyRedefineClasses() to determine if the redefinition can change the schema, delete methods, change the class hierarchy, etc. 
Params:
  • classToBytes – A map from ReferenceType to array of byte. The bytes represent the new class definition and are in Java Virtual Machine class file format.
Throws:
See Also:
Since:1.4
/**
     * All classes given are redefined according to the
     * definitions supplied.  A method in a redefined class
     * is called 'equivalent' (to the old version of the
     * method) if
     * <UL>
     * <LI>their bytecodes are the same except for indicies into
     *   the constant pool, and
     * <LI>the referenced constants are equal.
     * </UL>
     * Otherwise, the new method is called 'non-equivalent'.
     * If a redefined method has active stack frames, those active
     * frames continue to run the bytecodes of the previous version of the
     * method.  If the new version of such a method is non-equivalent,
     * then a method from one of these active frames is called 'obsolete' and
     * {@link Method#isObsolete Method.isObsolete()}
     * will return true when called on one of these methods.
     * If resetting such a frame is desired, use
     * {@link ThreadReference#popFrames ThreadReference.popFrames(StackFrame)}
     * to pop the old obsolete method execution from the stack.
     * New invocations of redefined methods will always invoke the new versions.
     * <p>
     * This function does not cause any initialization except
     * that which would occur under the customary JVM semantics.
     * In other words, redefining a class does not cause
     * its initializers to be run. The values of preexisting
     * static variables will remain as they were prior to the
     * call. However, completely uninitialized (new) static
     * variables will be assigned their default value.
     * <p>
     * If a redefined class has instances then all those
     * instances will have the fields defined by the redefined
     * class at the completion of the call. Preexisting fields
     * will retain their previous values. Any new fields will
     * have their default values; no instance initializers or
     * constructors are run.
     * <p>
     * Threads need not be suspended.
     * <p>
     * No events are generated by this function.
     * <p>
     * All breakpoints in the redefined classes are deleted.
     * <p>
     * Not all target virtual machines support this operation.
     * Use {@link #canRedefineClasses() canRedefineClasses()}
     * to determine if the operation is supported.
     * Use {@link #canAddMethod() canAddMethod()}
     * to determine if the redefinition can add methods.
     * Use {@link #canUnrestrictedlyRedefineClasses() canUnrestrictedlyRedefineClasses()}
     * to determine if the redefinition can change the schema,
     * delete methods, change the class hierarchy, etc.
     *
     * @param classToBytes A map from {@link ReferenceType}
     * to array of byte.
     * The bytes represent the new class definition and
     * are in Java Virtual Machine class file format.
     *
     * @throws java.lang.UnsupportedOperationException if
     * the target virtual machine does not support this
     * operation.
     * <UL>
     * <LI>If {@link #canRedefineClasses() canRedefineClasses()}
     * is false any call of this method will throw this exception.
     * <LI>If {@link #canAddMethod() canAddMethod()} is false
     * attempting to add a method will throw this exception.
     * <LI>If {@link #canUnrestrictedlyRedefineClasses()
     *            canUnrestrictedlyRedefineClasses()}
     * is false, attempting any of the following will throw
     * this exception
     *   <UL>
     *   <LI>changing the schema (the fields)
     *   <LI>changing the hierarchy (subclasses, interfaces)
     *   <LI>deleting a method
     *   <LI>changing class modifiers
     *   <LI>changing method modifiers
     *   </UL>
     * </UL>
     *
     * @throws java.lang.NoClassDefFoundError if the bytes
     * don't correspond to the reference type (the names
     * don't match).
     *
     * @throws java.lang.VerifyError if a "verifier" detects
     * that a class, though well formed, contains an internal
     * inconsistency or security problem.
     *
     * @throws java.lang.ClassFormatError if the bytes
     * do not represent a valid class.
     *
     * @throws java.lang.ClassCircularityError if a
     * circularity has been detected while initializing a class.
     *
     * @throws java.lang.UnsupportedClassVersionError if the
     * major and minor version numbers in bytes
     * are not supported by the VM.
     *
     * @throws VMCannotBeModifiedException if the VirtualMachine is read-only - see {@link VirtualMachine#canBeModified()}.
     *
     * @see Method#isObsolete
     * @see ThreadReference#popFrames
     * @see #canRedefineClasses
     * @see #canAddMethod
     * @see #canUnrestrictedlyRedefineClasses
     *
     * @since 1.4
     */
    void redefineClasses(Map<? extends ReferenceType,byte[]> classToBytes);

    
Returns a list of the currently running threads. For each running thread in the target VM, a ThreadReference that mirrors it is placed in the list. The returned list contains threads created through java.lang.Thread, all native threads attached to the target VM through JNI, and system threads created by the target VM. Thread objects that have not yet been started (see Thread.start()) and thread objects that have completed their execution are not included in the returned list. 
Returns:a list of ThreadReference objects, one for each running thread in the mirrored VM.
/**
     * Returns a list of the currently running threads. For each
     * running thread in the target VM, a {@link ThreadReference}
     * that mirrors it is placed in the list.
     * The returned list contains threads created through
     * java.lang.Thread, all native threads attached to
     * the target VM through JNI, and system threads created
     * by the target VM. Thread objects that have
     * not yet been started
     * (see {@link java.lang.Thread#start Thread.start()})
     * and thread objects that have
     * completed their execution are not included in the returned list.
     *
     * @return a list of {@link ThreadReference} objects, one for each
     * running thread in the mirrored VM.
     */
    List<ThreadReference> allThreads();

    
Suspends the execution of the application running in this
virtual machine. All threads currently running will be suspended.

 Unlike Thread.suspend(), suspends of both the virtual machine and individual threads are counted. Before a thread will run again, it must be resumed (through resume or ThreadReference.resume) the same number of times it has been suspended. 
Throws:
/**
     * Suspends the execution of the application running in this
     * virtual machine. All threads currently running will be suspended.
     * <p>
     * Unlike {@link java.lang.Thread#suspend Thread.suspend()},
     * suspends of both the virtual machine and individual threads are
     * counted. Before a thread will run again, it must be resumed
     * (through {@link #resume} or {@link ThreadReference#resume})
     * the same number of times it has been suspended.
     *
     * @throws VMCannotBeModifiedException if the VirtualMachine is read-only - see {@link VirtualMachine#canBeModified()}.
     */
    void suspend();

    
Continues the execution of the application running in this virtual machine. All threads are resumed as documented in ThreadReference.resume. 
Throws:
See Also:
/**
     * Continues the execution of the application running in this
     * virtual machine. All threads are resumed as documented in
     * {@link ThreadReference#resume}.
     *
     * @throws VMCannotBeModifiedException if the VirtualMachine is read-only - see {@link VirtualMachine#canBeModified()}.
     *
     * @see #suspend
     */
    void resume();

    
Returns each thread group which does not have a parent. For each top level thread group a ThreadGroupReference is placed in the returned list. 

This command may be used as the first step in building a tree
(or trees) of the existing thread groups.

Returns:a list of ThreadGroupReference objects, one for each top level thread group.
/**
     * Returns each thread group which does not have a parent. For each
     * top level thread group a {@link ThreadGroupReference} is placed in the
     * returned list.
     * <p>
     * This command may be used as the first step in building a tree
     * (or trees) of the existing thread groups.
     *
     * @return a list of {@link ThreadGroupReference} objects, one for each
     * top level thread group.
     */
    List<ThreadGroupReference> topLevelThreadGroups();

    
Returns the event queue for this virtual machine. A virtual machine has only one EventQueue object, this method will return the same instance each time it is invoked. 
Throws:
Returns:the EventQueue for this virtual machine.
/**
     * Returns the event queue for this virtual machine.
     * A virtual machine has only one {@link EventQueue} object, this
     * method will return the same instance each time it
     * is invoked.
     *
     * @throws VMCannotBeModifiedException if the VirtualMachine is read-only - see {@link VirtualMachine#canBeModified()}.
     *
     * @return the {@link EventQueue} for this virtual machine.
     */
    EventQueue eventQueue();

    
Returns the event request manager for this virtual machine. The EventRequestManager controls user settable events such as breakpoints. A virtual machine has only one EventRequestManager object, this method will return the same instance each time it is invoked. 
Throws:
Returns:the EventRequestManager for this virtual machine.
/**
     * Returns the event request manager for this virtual machine.
     * The {@link EventRequestManager} controls user settable events
     * such as breakpoints.
     * A virtual machine has only one {@link EventRequestManager} object,
     * this method will return the same instance each time it
     * is invoked.
     *
     * @throws VMCannotBeModifiedException if the VirtualMachine is read-only - see {@link VirtualMachine#canBeModified()}.
     *
     * @return the {@link EventRequestManager} for this virtual machine.
     */
    EventRequestManager eventRequestManager();

    
Creates a BooleanValue for the given value. This value can be used for setting and comparing against a value retrieved from a variable or field in this virtual machine. 
Params:
  • value – a boolean for which to create the value
Returns:the BooleanValue for the given boolean.
/**
     * Creates a {@link BooleanValue} for the given value. This value
     * can be used for setting and comparing against a value retrieved
     * from a variable or field in this virtual machine.
     *
     * @param value a boolean for which to create the value
     * @return the {@link BooleanValue} for the given boolean.
     */
    BooleanValue mirrorOf(boolean value);

    
Creates a ByteValue for the given value. This value can be used for setting and comparing against a value retrieved from a variable or field in this virtual machine. 
Params:
  • value – a byte for which to create the value
Returns:the ByteValue for the given byte.
/**
     * Creates a {@link ByteValue} for the given value. This value
     * can be used for setting and comparing against a value retrieved
     * from a variable or field in this virtual machine.
     *
     * @param value a byte for which to create the value
     * @return the {@link ByteValue} for the given byte.
     */
    ByteValue mirrorOf(byte value);

    
Creates a CharValue for the given value. This value can be used for setting and comparing against a value retrieved from a variable or field in this virtual machine. 
Params:
  • value – a char for which to create the value
Returns:the CharValue for the given char.
/**
     * Creates a {@link CharValue} for the given value. This value
     * can be used for setting and comparing against a value retrieved
     * from a variable or field in this virtual machine.
     *
     * @param value a char for which to create the value
     * @return the {@link CharValue} for the given char.
     */
    CharValue mirrorOf(char value);

    
Creates a ShortValue for the given value. This value can be used for setting and comparing against a value retrieved from a variable or field in this virtual machine. 
Params:
  • value – a short for which to create the value
Returns:the ShortValue for the given short.
/**
     * Creates a {@link ShortValue} for the given value. This value
     * can be used for setting and comparing against a value retrieved
     * from a variable or field in this virtual machine.
     *
     * @param value a short for which to create the value
     * @return the {@link ShortValue} for the given short.
     */
    ShortValue mirrorOf(short value);

    
Creates an IntegerValue for the given value. This value can be used for setting and comparing against a value retrieved from a variable or field in this virtual machine. 
Params:
  • value – an int for which to create the value
Returns:the IntegerValue for the given int.
/**
     * Creates an {@link IntegerValue} for the given value. This value
     * can be used for setting and comparing against a value retrieved
     * from a variable or field in this virtual machine.
     *
     * @param value an int for which to create the value
     * @return the {@link IntegerValue} for the given int.
     */
    IntegerValue mirrorOf(int value);

    
Creates a LongValue for the given value. This value can be used for setting and comparing against a value retrieved from a variable or field in this virtual machine. 
Params:
  • value – a long for which to create the value
Returns:the LongValue for the given long.
/**
     * Creates a {@link LongValue} for the given value. This value
     * can be used for setting and comparing against a value retrieved
     * from a variable or field in this virtual machine.
     *
     * @param value a long for which to create the value
     * @return the {@link LongValue} for the given long.
     */
    LongValue mirrorOf(long value);

    
Creates a FloatValue for the given value. This value can be used for setting and comparing against a value retrieved from a variable or field in this virtual machine. 
Params:
  • value – a float for which to create the value
Returns:the FloatValue for the given float.
/**
     * Creates a {@link FloatValue} for the given value. This value
     * can be used for setting and comparing against a value retrieved
     * from a variable or field in this virtual machine.
     *
     * @param value a float for which to create the value
     * @return the {@link FloatValue} for the given float.
     */
    FloatValue mirrorOf(float value);

    
Creates a DoubleValue for the given value. This value can be used for setting and comparing against a value retrieved from a variable or field in this virtual machine. 
Params:
  • value – a double for which to create the value
Returns:the DoubleValue for the given double.
/**
     * Creates a {@link DoubleValue} for the given value. This value
     * can be used for setting and comparing against a value retrieved
     * from a variable or field in this virtual machine.
     *
     * @param value a double for which to create the value
     * @return the {@link DoubleValue} for the given double.
     */
    DoubleValue mirrorOf(double value);

    
Creates a string in this virtual machine.
The created string can be used for setting and comparing against
a string value retrieved from a variable or field in this
virtual machine.

Params:
  • value – the string to be created
Throws:
Returns:a StringReference that mirrors the newly created string in the target VM.
/**
     * Creates a string in this virtual machine.
     * The created string can be used for setting and comparing against
     * a string value retrieved from a variable or field in this
     * virtual machine.
     *
     * @param value the string to be created
     * @return a {@link StringReference} that mirrors the newly created
     * string in the target VM.
     * @throws VMCannotBeModifiedException if the VirtualMachine is read-only
     * -see {@link VirtualMachine#canBeModified()}.
     */
    StringReference mirrorOf(String value);


    
Creates a VoidValue. This value can be passed to ThreadReference.forceEarlyReturn when a void method is to be exited. 
Returns:the VoidValue.
/**
     * Creates a {@link VoidValue}.  This value
     * can be passed to {@link ThreadReference#forceEarlyReturn}
     * when a void method is to be exited.
     *
     * @return the {@link VoidValue}.
     */
    VoidValue mirrorOfVoid();

    
Returns the Process object for this virtual machine if launched by a LaunchingConnector 
Throws:
Returns:the Process object for this virtual machine, or null if it was not launched by a LaunchingConnector.
/**
     * Returns the {@link java.lang.Process} object for this
     * virtual machine if launched
     * by a {@link com.sun.jdi.connect.LaunchingConnector}
     *
     * @return the {@link java.lang.Process} object for this virtual
     * machine, or null if it was not launched by a
     * {@link com.sun.jdi.connect.LaunchingConnector}.
     * @throws VMCannotBeModifiedException if the VirtualMachine is read-only
     * -see {@link VirtualMachine#canBeModified()}.
     */
    Process process();

    
Invalidates this virtual machine mirror.
The communication channel to the target VM is closed, and
the target VM prepares to accept another subsequent connection
from this debugger or another debugger, including the
following tasks:

Any current method invocations executing in the target VM
are continued after the disconnection. Upon completion of any such
method invocation, the invoking thread continues from the
location where it was originally stopped.


Resources originating in
this VirtualMachine (ObjectReferences, ReferenceTypes, etc.)
will become invalid.

/**
     * Invalidates this virtual machine mirror.
     * The communication channel to the target VM is closed, and
     * the target VM prepares to accept another subsequent connection
     * from this debugger or another debugger, including the
     * following tasks:
     * <ul>
     * <li>All event requests are cancelled.
     * <li>All threads suspended by {@link #suspend} or by
     * {@link ThreadReference#suspend} are resumed as many
     * times as necessary for them to run.
     * <li>Garbage collection is re-enabled in all cases where it was
     * disabled through {@link ObjectReference#disableCollection}.
     * </ul>
     * Any current method invocations executing in the target VM
     * are continued after the disconnection. Upon completion of any such
     * method invocation, the invoking thread continues from the
     * location where it was originally stopped.
     * <p>
     * Resources originating in
     * this VirtualMachine (ObjectReferences, ReferenceTypes, etc.)
     * will become invalid.
     */
    void dispose();

    
Causes the mirrored VM to terminate with the given error code.
All resources associated with this VirtualMachine are freed.
If the mirrored VM is remote, the communication channel
to it will be closed. Resources originating in
this VirtualMachine (ObjectReferences, ReferenceTypes, etc.)
will become invalid.


Threads running in the mirrored VM are abruptly terminated.
A thread death exception is not thrown and
finally blocks are not run.

Params:
  • exitCode – the exit code for the target VM.  On some platforms,
the exit code might be truncated, for example, to the lower order 8 bits.
Throws:
/**
     * Causes the mirrored VM to terminate with the given error code.
     * All resources associated with this VirtualMachine are freed.
     * If the mirrored VM is remote, the communication channel
     * to it will be closed. Resources originating in
     * this VirtualMachine (ObjectReferences, ReferenceTypes, etc.)
     * will become invalid.
     * <p>
     * Threads running in the mirrored VM are abruptly terminated.
     * A thread death exception is not thrown and
     * finally blocks are not run.
     *
     * @param exitCode the exit code for the target VM.  On some platforms,
     * the exit code might be truncated, for example, to the lower order 8 bits.
     *
     * @throws VMCannotBeModifiedException if the VirtualMachine is read-only - see {@link VirtualMachine#canBeModified()}.
     */
    void exit(int exitCode);

    
Determines if the target VM supports watchpoints
for field modification.

Returns:true if the feature is supported,
false otherwise.
/**
     * Determines if the target VM supports watchpoints
     * for field modification.
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     */
    boolean canWatchFieldModification();

    
Determines if the target VM supports watchpoints
for field access.

Returns:true if the feature is supported,
false otherwise.
/**
     * Determines if the target VM supports watchpoints
     * for field access.
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     */
    boolean canWatchFieldAccess();

    
Determines if the target VM supports the retrieval
of a method's bytecodes.

Returns:true if the feature is supported,
false otherwise.
/**
     * Determines if the target VM supports the retrieval
     * of a method's bytecodes.
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     */
    boolean canGetBytecodes();

    
Determines if the target VM supports the query
of the synthetic attribute of a method or field.

Returns:true if the feature is supported,
false otherwise.
/**
     * Determines if the target VM supports the query
     * of the synthetic attribute of a method or field.
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     */
    boolean canGetSyntheticAttribute();

    
Determines if the target VM supports the retrieval
of the monitors owned by a thread.

Returns:true if the feature is supported,
false otherwise.
/**
     * Determines if the target VM supports the retrieval
     * of the monitors owned by a thread.
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     */
    boolean canGetOwnedMonitorInfo();

    
Determines if the target VM supports the retrieval
of the monitor for which a thread is currently waiting.

Returns:true if the feature is supported,
false otherwise.
/**
     * Determines if the target VM supports the retrieval
     * of the monitor for which a thread is currently waiting.
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     */
    boolean canGetCurrentContendedMonitor();

    
Determines if the target VM supports the retrieval
of the monitor information for an object.

Returns:true if the feature is supported,
false otherwise.
/**
     * Determines if the target VM supports the retrieval
     * of the monitor information for an object.
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     */
    boolean canGetMonitorInfo();

    
Determines if the target VM supports filtering events by specific instance object. For example, see BreakpointRequest.addInstanceFilter. 
Returns:true if the feature is supported,
false otherwise.
/**
     * Determines if the target VM supports filtering
     * events by specific instance object.  For example,
     * see {@link com.sun.jdi.request.BreakpointRequest#addInstanceFilter}.
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     */
    boolean canUseInstanceFilters();

    
Determines if the target VM supports any level
of class redefinition.

See Also:
  • redefineClasses
Returns:true if the feature is supported,
false otherwise.
Since:1.4
/**
     * Determines if the target VM supports any level
     * of class redefinition.
     * @see #redefineClasses
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.4
     */
    boolean canRedefineClasses();

    
Determines if the target VM supports the addition
of methods when performing class redefinition.

See Also:
  • redefineClasses
Returns:true if the feature is supported,
false otherwise.
Since:1.4
/**
     * Determines if the target VM supports the addition
     * of methods when performing class redefinition.
     * @see #redefineClasses
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.4
     */
    boolean canAddMethod();

    
Determines if the target VM supports unrestricted
changes when performing class redefinition.

See Also:
  • redefineClasses
Returns:true if the feature is supported,
false otherwise.
Since:1.4
/**
     * Determines if the target VM supports unrestricted
     * changes when performing class redefinition.
     * @see #redefineClasses
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.4
     */
    boolean canUnrestrictedlyRedefineClasses();

    
Determines if the target VM supports popping
frames of a threads stack.

See Also:
  • popFrames.popFrames
Returns:true if the feature is supported,
false otherwise.
Since:1.4
/**
     * Determines if the target VM supports popping
     * frames of a threads stack.
     * @see ThreadReference#popFrames
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.4
     */
    boolean canPopFrames();

    
Determines if the target VM supports getting
the source debug extension.

See Also:
  • sourceDebugExtension.sourceDebugExtension
Returns:true if the feature is supported,
false otherwise.
Since:1.4
/**
     * Determines if the target VM supports getting
     * the source debug extension.
     * @see ReferenceType#sourceDebugExtension
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.4
     */
    boolean canGetSourceDebugExtension();

    
Determines if the target VM supports the creation of VMDeathRequests. 
See Also:
Returns:true if the feature is supported,
false otherwise.
Since:1.4
/**
     * Determines if the target VM supports the creation of
     * {@link com.sun.jdi.request.VMDeathRequest}s.
     * @see com.sun.jdi.request.EventRequestManager#createVMDeathRequest
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.4
     */
    boolean canRequestVMDeathEvent();

    
Determines if the target VM supports the inclusion of return values in MethodExitEvents. 
See Also:
Returns:true if the feature is supported,
false otherwise.
Since:1.6
/**
     * Determines if the target VM supports the inclusion of return values
     * in
     * {@link com.sun.jdi.event.MethodExitEvent}s.
     * @see com.sun.jdi.request.EventRequestManager#createMethodExitRequest
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.6
     */
    boolean canGetMethodReturnValues();

    
Determines if the target VM supports the accessing of class instances,
instance counts, and referring objects.

See Also:
Returns:true if the feature is supported,
false otherwise.
Since:1.6
/**
     * Determines if the target VM supports the accessing of class instances,
     * instance counts, and referring objects.
     *
     * @see #instanceCounts
     * @see ReferenceType#instances(long)
     * @see ObjectReference#referringObjects(long)
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.6
     */
    boolean canGetInstanceInfo();


    
Determines if the target VM supports the filtering of class prepare events by source name. see ClassPrepareRequest.addSourceNameFilter. 
Returns:true if the feature is supported,
false otherwise.
Since:1.6
/**
     * Determines if the target VM supports the filtering of
     * class prepare events by source name.
     *
     * see {@link com.sun.jdi.request.ClassPrepareRequest#addSourceNameFilter}.
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.6
     */
    boolean canUseSourceNameFilters();

    
Determines if the target VM supports the forcing of a method to
return early.

See Also:
  • forceEarlyReturn.forceEarlyReturn(Value)
Returns:true if the feature is supported,
false otherwise.
Since:1.6
/**
     * Determines if the target VM supports the forcing of a method to
     * return early.
     *
     * @see ThreadReference#forceEarlyReturn(Value)
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.6
     */
    boolean canForceEarlyReturn();

    
Determines if the target VM is a read-only VM. If a method which would modify the state of the VM is called on a read-only VM, then VMCannotBeModifiedException is thrown. 
Returns:true if the feature is supported,
false otherwise.
Since:1.5
/**
     * Determines if the target VM is a read-only VM.  If a method which
     * would modify the state of the VM is called on a read-only VM,
     * then {@link VMCannotBeModifiedException} is thrown.
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.5
     */

    boolean canBeModified();

    
Determines if the target VM supports the creation of MonitorContendedEnterRequests. MonitorContendedEnteredRequests. MonitorWaitRequests. MonitorWaitedRequests. 
See Also:
Returns:true if the feature is supported,
false otherwise.
Since:1.6
/**
     * Determines if the target VM supports the creation of
     * {@link com.sun.jdi.request.MonitorContendedEnterRequest}s.
     * {@link com.sun.jdi.request.MonitorContendedEnteredRequest}s.
     * {@link com.sun.jdi.request.MonitorWaitRequest}s.
     * {@link com.sun.jdi.request.MonitorWaitedRequest}s.
     * @see com.sun.jdi.request.EventRequestManager#createMonitorContendedEnterRequest
     * @see com.sun.jdi.request.EventRequestManager#createMonitorContendedEnteredRequest
     * @see com.sun.jdi.request.EventRequestManager#createMonitorWaitRequest
     * @see com.sun.jdi.request.EventRequestManager#createMonitorWaitedRequest
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.6
     */

    boolean canRequestMonitorEvents();

    
Determines if the target VM supports getting which
frame has acquired a monitor.

See Also:
  • ownedMonitorsAndFrames.ownedMonitorsAndFrames
Returns:true if the feature is supported,
false otherwise.
Since:1.6
/**
     * Determines if the target VM supports getting which
     * frame has acquired a monitor.
     * @see com.sun.jdi.ThreadReference#ownedMonitorsAndFrames
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.6
     */

     boolean canGetMonitorFrameInfo();


    
Determines if the target VM supports reading class file
major and minor versions.

See Also:
Returns:true if the feature is supported,
false otherwise.
Since:1.6
/**
     * Determines if the target VM supports reading class file
     * major and minor versions.
     *
     * @see ReferenceType#majorVersion()
     * @see ReferenceType#minorVersion()
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.6
     */
    boolean canGetClassFileVersion();

    
Determines if the target VM supports getting constant pool
information of a class.

See Also:
Returns:true if the feature is supported,
false otherwise.
Since:1.6
/**
     * Determines if the target VM supports getting constant pool
     * information of a class.
     *
     * @see ReferenceType#constantPoolCount()
     * @see ReferenceType#constantPool()
     *
     * @return <code>true</code> if the feature is supported,
     * <code>false</code> otherwise.
     *
     * @since 1.6
     */
    boolean canGetConstantPool();

    
Set this VM's default stratum (see Location for a discussion of strata). Overrides the per-class default set in the class file. 
 Affects location queries (such as, Location.sourceName()) and the line boundaries used in single stepping. 
Params:
  • stratum – the stratum to set as VM default,
or null to use per-class defaults.
Throws:
Since:1.4
/**
     * Set this VM's default stratum (see {@link Location} for a
     * discussion of strata).  Overrides the per-class default set
     * in the class file.
     * <P>
     * Affects location queries (such as,
     * {@link Location#sourceName()})
     * and the line boundaries used in
     * single stepping.
     *
     * @param stratum the stratum to set as VM default,
     * or null to use per-class defaults.
     *
     * @throws java.lang.UnsupportedOperationException if the
     * target virtual machine does not support this operation.
     *
     * @since 1.4
     */
    void setDefaultStratum(String stratum);

    
Return this VM's default stratum.

See Also:
Returns:null (meaning that the per-class default - ReferenceType.defaultStratum() - should be used) unless the default stratum has been set with setDefaultStratum(String).
Since:1.4
/**
     * Return this VM's default stratum.
     *
     * @see #setDefaultStratum(String)
     * @see ReferenceType#defaultStratum()
     * @return <code>null</code> (meaning that the per-class
     * default - {@link ReferenceType#defaultStratum()} -
     * should be used) unless the default stratum has been
     * set with
     * {@link #setDefaultStratum(String)}.
     *
     * @since 1.4
     */
    String getDefaultStratum();

    
Returns the number of instances of each ReferenceType in the 'refTypes'
list.
Only instances that are reachable for the purposes of garbage collection
are counted.

 Not all target virtual machines support this operation. Use canGetInstanceInfo() to determine if the operation is supported. 
Params:
  • refTypes – the list of ReferenceType objects for which counts are to be obtained.
Throws:
See Also:
Returns:an array of long containing one element for each
        element in the 'refTypes' list.  Element i of the array contains
        the number of instances in the target VM of the ReferenceType at
        position i in the 'refTypes' list.
        If the 'refTypes' list is empty, a zero-length array is returned.
        If a ReferenceType in refTypes has been garbage collected, zero
        is returned for its instance count.
Since:1.6
/**
     * Returns the number of instances of each ReferenceType in the 'refTypes'
     * list.
     * Only instances that are reachable for the purposes of garbage collection
     * are counted.
     * <p>
     * Not all target virtual machines support this operation.
     * Use {@link VirtualMachine#canGetInstanceInfo()}
     * to determine if the operation is supported.
     *
     * @see ReferenceType#instances(long)
     * @see ObjectReference#referringObjects(long)
     * @param refTypes the list of {@link ReferenceType} objects for which counts
     *        are to be obtained.
     *
     * @return an array of <code>long</code> containing one element for each
     *         element in the 'refTypes' list.  Element i of the array contains
     *         the number of instances in the target VM of the ReferenceType at
     *         position i in the 'refTypes' list.
     *         If the 'refTypes' list is empty, a zero-length array is returned.
     *         If a ReferenceType in refTypes has been garbage collected, zero
     *         is returned for its instance count.
     * @throws java.lang.UnsupportedOperationException if
     * the target virtual machine does not support this
     * operation - see
     * {@link VirtualMachine#canGetInstanceInfo() canGetInstanceInfo()}
     * @throws NullPointerException if the 'refTypes' list is null.
     * @since 1.6
     */
    long[] instanceCounts(List<? extends ReferenceType> refTypes);

    
Returns text information on the target VM and the debugger support that mirrors it. No specific format for this information is guaranteed. Typically, this string contains version information for the target VM and debugger interfaces. More precise information on VM and JDI versions is available through version, VirtualMachineManager.majorInterfaceVersion, and VirtualMachineManager.minorInterfaceVersion 
Returns:the description.
/**
     * Returns text information on the target VM and the
     * debugger support that mirrors it. No specific format
     * for this information is guaranteed.
     * Typically, this string contains version information for the
     * target VM and debugger interfaces.
     * More precise information
     * on VM and JDI versions is available through
     * {@link #version}, {@link VirtualMachineManager#majorInterfaceVersion},
     * and {@link VirtualMachineManager#minorInterfaceVersion}
     *
     * @return the description.
     */
    String description();

    
Returns the version of the Java Runtime Environment in the target
VM as reported by the property java.version. For obtaining the JDI interface version, use VirtualMachineManager.majorInterfaceVersion and VirtualMachineManager.minorInterfaceVersion 
Returns:the target VM version.
/**
     * Returns the version of the Java Runtime Environment in the target
     * VM as reported by the property <code>java.version</code>.
     * For obtaining the JDI interface version, use
     * {@link VirtualMachineManager#majorInterfaceVersion}
     * and {@link VirtualMachineManager#minorInterfaceVersion}
     *
     * @return the target VM version.
     */
    String version();

    
Returns the name of the target VM as reported by the
property java.vm.name.

Returns:the target VM name.
/**
     * Returns the name of the target VM as reported by the
     * property <code>java.vm.name</code>.
     *
     * @return the target VM name.
     */
    String name();

    
All tracing is disabled. 
/** All tracing is disabled. */
    int TRACE_NONE        = 0x00000000;
    
Tracing enabled for JDWP packets sent to target VM. 
/** Tracing enabled for JDWP packets sent to target VM. */
    int TRACE_SENDS       = 0x00000001;
    
Tracing enabled for JDWP packets received from target VM. 
/** Tracing enabled for JDWP packets received from target VM. */
    int TRACE_RECEIVES    = 0x00000002;
    
Tracing enabled for internal event handling. 
/** Tracing enabled for internal event handling. */
    int TRACE_EVENTS      = 0x00000004;
    
Tracing enabled for internal managment of reference types. 
/** Tracing enabled for internal managment of reference types. */
    int TRACE_REFTYPES    = 0x00000008;
    
Tracing enabled for internal management of object references. 
/** Tracing enabled for internal management of object references. */
    int TRACE_OBJREFS      = 0x00000010;
    
All tracing is enabled. 
/** All tracing is enabled. */
    int TRACE_ALL         = 0x00ffffff;

    
Traces the activities performed by the com.sun.jdi implementation.
All trace information is output to System.err. The given trace
flags are used to limit the output to only the information
desired. The given flags are in effect and the corresponding
trace will continue until the next call to
this method.


Output is implementation dependent and trace mode may be ignored.

Params:
  • traceFlags – identifies which kinds of tracing to enable.
/**
     * Traces the activities performed by the com.sun.jdi implementation.
     * All trace information is output to System.err. The given trace
     * flags are used to limit the output to only the information
     * desired. The given flags are in effect and the corresponding
     * trace will continue until the next call to
     * this method.
     * <p>
     * Output is implementation dependent and trace mode may be ignored.
     *
     * @param traceFlags identifies which kinds of tracing to enable.
     */
    void setDebugTraceMode(int traceFlags);
}