Class SocketHandler

java.util.logging.SocketHandler

public class SocketHandler extends StreamHandler

Simple network logging Handler.

LogRecords are published to a network stream connection. By default the XMLFormatter class is used for formatting.

Configuration: By default each SocketHandler is initialized using the following LogManager configuration properties where <handler-name> refers to the fully-qualified class name of the handler. If properties are not defined (or have invalid values) then the specified default values are used.

<handler-name>.level specifies the default level for the Handler (defaults to Level.ALL).
<handler-name>.filter specifies the name of a Filter class to use (defaults to no Filter).
<handler-name>.formatter specifies the name of a Formatter class to use (defaults to java.util.logging.XMLFormatter).
<handler-name>.encoding the name of the character set encoding to use (defaults to the default platform encoding).
<handler-name>.host specifies the target host name to connect to (no default).
<handler-name>.port specifies the target TCP port to use (no default).

For example, the properties for SocketHandler would be:

java.util.logging.SocketHandler.level=INFO
java.util.logging.SocketHandler.formatter=java.util.logging.SimpleFormatter

For a custom handler, e.g. com.foo.MyHandler, the properties would be:

com.foo.MyHandler.level=INFO
com.foo.MyHandler.formatter=java.util.logging.SimpleFormatter

The output IO stream is buffered, but is flushed after each LogRecord is written.

Since:: 1.4

Constructor Summary

Constructor	Description
`SocketHandler()`	Create a `SocketHandler`, using only `LogManager` properties (or their defaults).
`SocketHandler(String host, int port)`	Construct a `SocketHandler` using a specified host and port.

Method Summary

Modifier and Type	Method	Description
`void`	`close()`	Close this output stream.
`void`	`publish(LogRecord record)`	Format and publish a `LogRecord`.

Methods declared in class StreamHandler

flush, isLoggable, setEncoding, setOutputStream

Modifier and Type	Method	Description
`void`	`flush()`	Flush any buffered messages.
`boolean`	`isLoggable(LogRecord record)`	Check if this `Handler` would actually log a given `LogRecord`.
`void`	`setEncoding(String encoding)`	Set (or change) the character encoding used by this `Handler`.
`protected void`	`setOutputStream(OutputStream out)`	Change the output stream.

Methods declared in class Handler

getEncoding, getErrorManager, getFilter, getFormatter, getLevel, reportError, setErrorManager, setFilter, setFormatter, setLevel

Modifier and Type	Method	Description
`String`	`getEncoding()`	Return the character encoding for this `Handler`.
`ErrorManager`	`getErrorManager()`	Retrieves the ErrorManager for this Handler.
`Filter`	`getFilter()`	Get the current `Filter` for this `Handler`.
`Formatter`	`getFormatter()`	Return the `Formatter` for this `Handler`.
`Level`	`getLevel()`	Get the log level specifying which messages will be logged by this `Handler`.
`protected void`	`reportError(String msg, Exception ex, int code)`	Protected convenience method to report an error to this Handler's ErrorManager.
`void`	`setErrorManager(ErrorManager em)`	Define an ErrorManager for this Handler.
`void`	`setFilter(Filter newFilter)`	Set a `Filter` to control output on this `Handler`.
`void`	`setFormatter(Formatter newFormatter)`	Set a `Formatter`.
`void`	`setLevel(Level newLevel)`	Set the log level specifying which message levels will be logged by this `Handler`.

Methods declared in class Object

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

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`boolean`	`equals(Object obj)`	Indicates whether some other object is "equal to" this one.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`int`	`hashCode()`	Returns a hash code value for this object.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()`	Returns a string representation of the object.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Constructor Details

SocketHandler

public SocketHandler() throws IOException

Create a SocketHandler, using only LogManager properties (or their defaults).

Throws:: IllegalArgumentException - if the host or port are invalid or are not specified as LogManager properties.; IOException - if we are unable to connect to the target host and port.

SocketHandler

public SocketHandler(String host, int port) throws IOException

Construct a SocketHandler using a specified host and port. The SocketHandler is configured based on LogManager properties (or their default values) except that the given target host and port arguments are used. If the host argument is empty, but not null String then the localhost is used.

Parameters:: host - target host.; port - target port.
Throws:: IllegalArgumentException - if the host or port are invalid.; IOException - if we are unable to connect to the target host and port.

Method Details

close

public void close()

Close this output stream.

Overrides:: close in class StreamHandler

publish

public void publish(LogRecord record)

Format and publish a LogRecord.

Overrides:: publish in class StreamHandler
Implementation Requirements:: This method is not synchronized, and subclasses must not define overridden publish() methods to be synchronized if they call super.publish() or format user arguments. See the discussion in java.util.logging.Handler for more information.
Parameters:: record - description of the log event. A null record is silently ignored and is not published

© 1993, 2025, Oracle and/or its affiliates. All rights reserved.
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).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.