OpenJDK 27 · java.rmi.server.RemoteObject · APIdia, the JavaDoc alternative

Modifier and Type	Field and Description
protected transient RemoteRef	ref The object's remote reference.
private static final long	serialVersionUID indicate compatibility with JDK 1.1.x version of class

Access	Constructor and Description
protected	RemoteObject() Creates a remote object.
protected	RemoteObject(RemoteRef remote reference newref) Creates a remote object, initialized with the specified remote reference.

Modifier and Type	Method and Description
public boolean	Returns: true if these Objects are equal; false otherwise. equals(Object the Object to compare with obj) Overrides java.lang.Object.equals. Compares two remote objects for equality.
public RemoteRef	Returns: remote reference for the remote object getRef() Returns the remote reference for the remote object.
public int	hashCode() Overrides java.lang.Object.hashCode. Returns a hashcode for a remote object.
private void	readObject(ObjectInputStream the `ObjectInputStream` from which data is read in) `readObject` for custom serialization.
public String	toString() Overrides java.lang.Object.toString. Returns a String that represents the value of this remote object.
public static Remote	Returns: the stub for the remote object, `obj`. toStub(Remote the remote object whose stub is needed obj) Returns the stub for the remote object `obj` passed as a parameter.
private void	writeObject(ObjectOutputStream the `ObjectOutputStream` to which data is written out) `writeObject` for custom serialization.

ref	back to summary
protected transient RemoteRef ref The object's remote reference.

serialVersionUID	back to summary
private static final long serialVersionUID indicate compatibility with JDK 1.1.x version of class Annotations @Serial

RemoteObject	back to summary
protected RemoteObject() Creates a remote object.

RemoteObject	back to summary
protected RemoteObject(RemoteRef newref) Creates a remote object, initialized with the specified remote reference. Parameters newref:RemoteRef remote reference

Method Detail

equals back to summary

equals	back to summary
public boolean equals(Object obj) Overrides java.lang.Object.equals. Compares two remote objects for equality. Returns a boolean that indicates whether this remote object is equivalent to the specified Object. This method is used when a remote object is stored in a hashtable. If the specified Object is not itself an instance of RemoteObject, then this method delegates by returning the result of invoking the `equals` method of its parameter with this remote object as the argument. Parameters obj:Object the Object to compare with Returns:boolean true if these Objects are equal; false otherwise. See Also `java.util.Hashtable`

public boolean equals(Object obj)

Compares two remote objects for equality. Returns a boolean that indicates whether this remote object is equivalent to the specified Object. This method is used when a remote object is stored in a hashtable. If the specified Object is not itself an instance of RemoteObject, then this method delegates by returning the result of invoking the equals method of its parameter with this remote object as the argument.

Parameters

obj:Object: the Object to compare with

Returns:boolean

true if these Objects are equal; false otherwise.

See Also

java.util.Hashtable

getRef back to summary

getRef	back to summary
public RemoteRef getRef() Returns the remote reference for the remote object. Note The object returned from this method may be an instance of an implementation-specific class. The `RemoteObject` class ensures serialization portability of its instances' remote references through the behavior of its custom `writeObject` and `readObject` methods. An instance of `RemoteRef` should not be serialized outside of its `RemoteObject` wrapper instance or the result may be unportable. Returns:RemoteRef remote reference for the remote object Since 1.2

public RemoteRef getRef()

Returns the remote reference for the remote object.

Note

The object returned from this method may be an instance of an implementation-specific class. The RemoteObject class ensures serialization portability of its instances' remote references through the behavior of its custom writeObject and readObject methods. An instance of RemoteRef should not be serialized outside of its RemoteObject wrapper instance or the result may be unportable.

Returns:RemoteRef: remote reference for the remote object
Since: 1.2

hashCode back to summary

hashCode	back to summary
public int hashCode() Overrides java.lang.Object.hashCode. Returns a hashcode for a remote object. Two remote object stubs that refer to the same remote object will have the same hash code (in order to support remote objects as keys in hash tables). See Also `java.util.Hashtable`

public int hashCode()

Overrides java.lang.Object.hashCode.

Returns a hashcode for a remote object. Two remote object stubs that refer to the same remote object will have the same hash code (in order to support remote objects as keys in hash tables).

See Also: java.util.Hashtable

readObject back to summary

readObject	back to summary
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException `readObject` for custom serialization. This method reads this object's serialized form for this class as follows: The `readUTF` method is invoked on `in` to read the external ref type name for the `RemoteRef` instance to be filled in to this object's `ref` field. If the string returned by `readUTF` has length zero, the `readObject` method is invoked on `in`, and than the value returned by `readObject` is cast to `RemoteRef` and this object's `ref` field is set to that value. Otherwise, this object's `ref` field is set to a `RemoteRef` instance that is created of an implementation-specific class corresponding to the external ref type name returned by `readUTF`, and then the `readExternal` method is invoked on this object's `ref` field. If the external ref type name is `"UnicastRef"`, `"UnicastServerRef"`, `"UnicastRef2"`, or `"UnicastServerRef2"`, a corresponding implementation-specific class must be found, and its `readExternal` method must read the serial data for that external ref type name as specified to be written in the serialData documentation for this class. If the external ref type name is any other string (of non-zero length), a `ClassNotFoundException` will be thrown, unless the implementation provides an implementation-specific class corresponding to that external ref type name, in which case this object's `ref` field will be set to an instance of that implementation-specific class. Parameters in:ObjectInputStream the `ObjectInputStream` from which data is read Annotations @Serial Exceptions IOException: if an I/O error occurs ClassNotFoundException: if a serialized class cannot be loaded

private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException

readObject for custom serialization.

This method reads this object's serialized form for this class as follows:

The readUTF method is invoked on in to read the external ref type name for the RemoteRef instance to be filled in to this object's ref field. If the string returned by readUTF has length zero, the readObject method is invoked on in, and than the value returned by readObject is cast to RemoteRef and this object's ref field is set to that value. Otherwise, this object's ref field is set to a RemoteRef instance that is created of an implementation-specific class corresponding to the external ref type name returned by readUTF, and then the readExternal method is invoked on this object's ref field.

If the external ref type name is "UnicastRef", "UnicastServerRef", "UnicastRef2", or "UnicastServerRef2", a corresponding implementation-specific class must be found, and its readExternal method must read the serial data for that external ref type name as specified to be written in the serialData documentation for this class. If the external ref type name is any other string (of non-zero length), a ClassNotFoundException will be thrown, unless the implementation provides an implementation-specific class corresponding to that external ref type name, in which case this object's ref field will be set to an instance of that implementation-specific class.

Parameters

in:ObjectInputStream: the ObjectInputStream from which data is read

Annotations

@Serial

Exceptions

IOException:: if an I/O error occurs
ClassNotFoundException:: if a serialized class cannot be loaded

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Returns a String that represents the value of this remote object.

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Returns a String that represents the value of this remote object.

toStub back to summary

toStub	back to summary
public static Remote toStub(Remote obj) throws NoSuchObjectException Returns the stub for the remote object `obj` passed as a parameter. This operation is only valid after the object has been exported. Parameters obj:Remote the remote object whose stub is needed Returns:Remote the stub for the remote object, `obj`. Annotations @SuppressWarnings:deprecation Exceptions NoSuchObjectException: if the stub for the remote object could not be found. Since 1.2

public static Remote toStub(Remote obj) throws NoSuchObjectException

Returns the stub for the remote object obj passed as a parameter. This operation is only valid after the object has been exported.

Parameters

obj:Remote: the remote object whose stub is needed

Returns:Remote

the stub for the remote object, obj.

Annotations

@SuppressWarnings:deprecation

Exceptions

NoSuchObjectException:: if the stub for the remote object could not be found.

Since

1.2

writeObject back to summary

writeObject	back to summary
private void writeObject(ObjectOutputStream out) throws IOException `writeObject` for custom serialization. This method writes this object's serialized form for this class as follows: The `getRefClass` method is invoked on this object's `ref` field to obtain its external ref type name. If the value returned by `getRefClass` was a non-`null` string of length greater than zero, the `writeUTF` method is invoked on `out` with the value returned by `getRefClass`, and then the `writeExternal` method is invoked on this object's `ref` field passing `out` as the argument; otherwise, the `writeUTF` method is invoked on `out` with a zero-length string (`""`), and then the `writeObject` method is invoked on `out` passing this object's `ref` field as the argument. Parameters out:ObjectOutputStream the `ObjectOutputStream` to which data is written Annotations @Serial Exceptions IOException: if an I/O error occurs Serial data The serialized data for this class comprises a string (written with `ObjectOutput.writeUTF`) that is either the external ref type name of the contained `RemoteRef` instance (the `ref` field) or a zero-length string, followed by either the external form of the `ref` field as written by its `writeExternal` method if the string was of non-zero length, or the serialized form of the `ref` field as written by passing it to the serialization stream's `writeObject` if the string was of zero length. If this object is an instance of `RemoteStub` or `RemoteObjectInvocationHandler` that was returned from any of the `UnicastRemoteObject.exportObject` methods and custom socket factories are not used, the external ref type name is `"UnicastRef"`. If this object is an instance of `RemoteStub` or `RemoteObjectInvocationHandler` that was returned from any of the `UnicastRemoteObject.exportObject` methods and custom socket factories are used, the external ref type name is `"UnicastRef2"`. If this object is an instance of `RemoteStub` or `RemoteObjectInvocationHandler` that was returned from the `RemoteObject.toStub` method (and the argument passed to `toStub` was not itself a `RemoteStub`), the external ref type name is a function of how the remote object passed to `toStub` was exported, as described above. If this object is an instance of `RemoteStub` or `RemoteObjectInvocationHandler` that was originally created via deserialization, the external ref type name is the same as that which was read when this object was deserialized. If this object is an instance of `java.rmi.server.UnicastRemoteObject` that does not use custom socket factories, the external ref type name is `"UnicastServerRef"`. If this object is an instance of `UnicastRemoteObject` that does use custom socket factories, the external ref type name is `"UnicastServerRef2"`. Following is the data that must be written by the `writeExternal` method and read by the `readExternal` method of `RemoteRef` implementation classes that correspond to the each of the defined external ref type names: For `"UnicastRef"`: the hostname of the referenced remote object, written by `java.io.ObjectOutput#writeUTF(String)` the port of the referenced remote object, written by `java.io.ObjectOutput#writeInt(int)` the data written as a result of calling `java.rmi.server.ObjID#write(java.io.ObjectOutput)` on the `ObjID` instance contained in the reference the boolean value `false`, written by `java.io.ObjectOutput#writeBoolean(boolean)` For `"UnicastRef2"` with a `null` client socket factory: the byte value `0x00` (indicating `null` client socket factory), written by `java.io.ObjectOutput#writeByte(int)` the hostname of the referenced remote object, written by `java.io.ObjectOutput#writeUTF(String)` the port of the referenced remote object, written by `java.io.ObjectOutput#writeInt(int)` the data written as a result of calling `java.rmi.server.ObjID#write(java.io.ObjectOutput)` on the `ObjID` instance contained in the reference the boolean value `false`, written by `java.io.ObjectOutput#writeBoolean(boolean)` For `"UnicastRef2"` with a non-`null` client socket factory: the byte value `0x01` (indicating non-`null` client socket factory), written by `java.io.ObjectOutput#writeByte(int)` the hostname of the referenced remote object, written by `java.io.ObjectOutput#writeUTF(String)` the port of the referenced remote object, written by `java.io.ObjectOutput#writeInt(int)` a client socket factory (object of type `java.rmi.server.RMIClientSocketFactory`), written by passing it to an invocation of `writeObject` on the stream instance the data written as a result of calling `java.rmi.server.ObjID#write(java.io.ObjectOutput)` on the `ObjID` instance contained in the reference the boolean value `false`, written by `java.io.ObjectOutput#writeBoolean(boolean)` For `"UnicastServerRef"` and `"UnicastServerRef2"`, no data is written by the `writeExternal` method or read by the `readExternal` method.

private void writeObject(ObjectOutputStream out) throws IOException

writeObject for custom serialization.

This method writes this object's serialized form for this class as follows:

The getRefClass method is invoked on this object's ref field to obtain its external ref type name. If the value returned by getRefClass was a non-null string of length greater than zero, the writeUTF method is invoked on out with the value returned by getRefClass, and then the writeExternal method is invoked on this object's ref field passing out as the argument; otherwise, the writeUTF method is invoked on out with a zero-length string (""), and then the writeObject method is invoked on out passing this object's ref field as the argument.

Parameters

out:ObjectOutputStream: the ObjectOutputStream to which data is written

Annotations

@Serial

Exceptions

IOException:: if an I/O error occurs

Serial data

The serialized data for this class comprises a string (written with ObjectOutput.writeUTF) that is either the external ref type name of the contained RemoteRef instance (the ref field) or a zero-length string, followed by either the external form of the ref field as written by its writeExternal method if the string was of non-zero length, or the serialized form of the ref field as written by passing it to the serialization stream's writeObject if the string was of zero length.

If this object is an instance of RemoteStub or RemoteObjectInvocationHandler that was returned from any of the UnicastRemoteObject.exportObject methods and custom socket factories are not used, the external ref type name is "UnicastRef". If this object is an instance of RemoteStub or RemoteObjectInvocationHandler that was returned from any of the UnicastRemoteObject.exportObject methods and custom socket factories are used, the external ref type name is "UnicastRef2". If this object is an instance of RemoteStub or RemoteObjectInvocationHandler that was returned from the RemoteObject.toStub method (and the argument passed to toStub was not itself a RemoteStub), the external ref type name is a function of how the remote object passed to toStub was exported, as described above. If this object is an instance of RemoteStub or RemoteObjectInvocationHandler that was originally created via deserialization, the external ref type name is the same as that which was read when this object was deserialized.

If this object is an instance of java.rmi.server.UnicastRemoteObject that does not use custom socket factories, the external ref type name is "UnicastServerRef". If this object is an instance of UnicastRemoteObject that does use custom socket factories, the external ref type name is "UnicastServerRef2".

Following is the data that must be written by the writeExternal method and read by the readExternal method of RemoteRef implementation classes that correspond to the each of the defined external ref type names:

For "UnicastRef":

the hostname of the referenced remote object, written by java.io.ObjectOutput#writeUTF(String)
the port of the referenced remote object, written by java.io.ObjectOutput#writeInt(int)
the data written as a result of calling java.rmi.server.ObjID#write(java.io.ObjectOutput) on the ObjID instance contained in the reference
the boolean value false, written by java.io.ObjectOutput#writeBoolean(boolean)

For "UnicastRef2" with a null client socket factory:

the byte value 0x00 (indicating null client socket factory), written by java.io.ObjectOutput#writeByte(int)
the hostname of the referenced remote object, written by java.io.ObjectOutput#writeUTF(String)
the port of the referenced remote object, written by java.io.ObjectOutput#writeInt(int)
the data written as a result of calling java.rmi.server.ObjID#write(java.io.ObjectOutput) on the ObjID instance contained in the reference
the boolean value false, written by java.io.ObjectOutput#writeBoolean(boolean)

For "UnicastRef2" with a non-null client socket factory:

the byte value 0x01 (indicating non-null client socket factory), written by java.io.ObjectOutput#writeByte(int)
the hostname of the referenced remote object, written by java.io.ObjectOutput#writeUTF(String)
the port of the referenced remote object, written by java.io.ObjectOutput#writeInt(int)
a client socket factory (object of type java.rmi.server.RMIClientSocketFactory), written by passing it to an invocation of writeObject on the stream instance
the data written as a result of calling java.rmi.server.ObjID#write(java.io.ObjectOutput) on the ObjID instance contained in the reference
the boolean value false, written by java.io.ObjectOutput#writeBoolean(boolean)

For "UnicastServerRef" and "UnicastServerRef2", no data is written by the writeExternal method or read by the readExternal method.

public abstract Class RemoteObject

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail