Configuration properties

If true, classes are only loaded using the same classloader that loaded Log4j.

Otherwise, an attempt is made to load classes with the current thread’s context class loader before falling back to the default class loader.

Fully qualified class name of the Log4j API Provider to use.

By default, Log4j uses ServiceLoader to select the provider to use. In case multiple providers are found on the classpath the provider with the highest priority is selected and a WARN message is logger by Status Logger.

Fully qualified class name of the LoggerContextFactory to use to create Loggers.

By default, Log4j uses Provider.getLoggerContextFactory() to get a logger context factory. If log4j2.provider is set, this property is ignored.

If false, Log4j will make sure the message is formatted in the caller thread, otherwise the formatting will occur on the asynchronous thread.

Remark: messages annotated with AsynchronouslyFormattable will be formatted on the async thread regardless of this setting.

Determines the AsyncQueueFullPolicy to use when the underlying async component cannot keep up with the logging rate and the queue is filling up.

Its value should be the fully qualified class name of an AsyncQueueFullPolicy implementation or one of these predefined constants:

Determines the threshold level used by a Discard queue full policy. Log events whose level is not more severe than the threshold level will be discarded during a queue full event. See also log4j2.asyncQueueFullPolicy.

Fully qualified name of a class that implements the ExceptionHandler interface, which will be notified when an exception occurs while logging messages. The class needs to have a public zero-argument constructor.

The default exception handler will print a message and stack trace to the standard error output stream.

Size (number of slots) in the RingBuffer used by the asynchronous logging subsystem. Make this value large enough to deal with bursts of activity. The minimum size is 128. The RingBuffer will be pre-allocated at first use and will never grow or shrink during the life of the system.

When the application is logging faster than the underlying appender can keep up with for a long enough time to fill up the queue, the behaviour is determined by the AsyncQueueFullPolicy.

Specifies the WaitStrategy used by the LMAX Disruptor.

The value needs to be one of the predefined constants:

Timeout in milliseconds of Timeout wait strategy (see log4j2.asyncLoggerWaitStrategy).

Sleep time in nanoseconds of Sleep wait strategy (see log4j2.asyncLoggerWaitStrategy).

Total number of spin cycles and Thread.yield() cycles of Sleep (see log4j2.asyncLoggerWaitStrategy).

Synchronizes access to the Disruptor ring buffer for blocking enqueue operations when the queue is full. Users encountered excessive CPU utilization with Disruptor v3.4.2 when the application was logging more than the underlying appender could keep up with and the ring buffer became full, especially when the number of application threads vastly outnumbered the number of cores. CPU utilization is significantly reduced by restricting access to the enqueue operation. Setting this value to false may lead to very high CPU utilization when the async logging queue is full.

Specifies the ThreadNameCachingStrategy to use to cache the result of Thread#getName().

This setting allows to cache the result of Thread.getName() calls and has two values:

Fully qualified name of a class that implements the ExceptionHandler interface, which will be notified when an exception occurs while logging messages. The class needs to have a public zero-argument constructor.

The default exception handler will print a message and stack trace to the standard error output stream.

Size (number of slots) in the RingBuffer used by the asynchronous logging subsystem. Make this value large enough to deal with bursts of activity. The minimum size is 128. The RingBuffer will be pre-allocated at first use and will never grow or shrink during the life of the system.

When the application is logging faster than the underlying appender can keep up with for a long enough time to fill up the queue, the behaviour is determined by the AsyncQueueFullPolicy.

Specifies the WaitStrategy used by the LMAX Disruptor.

The value needs to be one of the predefined constants:

See also Custom WaitStrategy for an alternative way to configure the wait strategy.

Timeout in milliseconds of Timeout wait strategy (see log4j2.asyncLoggerConfigWaitStrategy).

Sleep time in nanoseconds of Sleep wait strategy (see log4j2.asyncLoggerConfigWaitStrategy)).

Total number of spin cycles and Thread.yield() cycles of Sleep (see log4j2.asyncLoggerConfigWaitStrategy)).

Synchronizes access to the Disruptor ring buffer for blocking enqueue operations when the queue is full. Users encountered excessive CPU utilization with Disruptor v3.4.2 when the application was logging more than the underlying appender could keep up with and the ring buffer became full, especially when the number of application threads vastly outnumbered the number of cores. CPU utilization is significantly reduced by restricting access to the enqueue operation. Setting this value to false may lead to very high CPU utilization when the async logging queue is full.

Specifies the fully qualified class name of the ContextSelector implementation to use.

The implementations available by default are:

Specifies the fully qualified class name of the preferred ConfigurationFactory to use.

Log4j will attempt to use the provided configuration factory before any other factory implementation.

Specifies a comma-separated list of URIs or file paths to Log4j 2 configuration files.

If a relative URL is provided, it is interpreted as:

Usage of absolute URLs is restricted by the Transport Security configuration options.

See also Automatic Configuration.

Specifies the level of the root logger if:

Specifies the fully qualified class name of the MergeStrategy implementation used to merge multiple configuration files into one.

If true, garbage-aware layouts will directly encode log events into ByteBuffers provided by appenders.

This prevents allocating temporary String and char[] instances.

The size in bytes of the ByteBuffers stored in ThreadLocal fields by layouts and StringBuilderEncoders.

This setting is only used if log4j2.enableDirectEncoders is set to true.

The size in chars of the ByteBuffers stored in ThreadLocal fields StringBuilderEncoders.

This setting is only used if log4j2.enableDirectEncoders is set to true.

In GC-free mode, this property determines the initial size of the reusable StringBuilders used by ReusableMessages for formatting purposes.

In GC-free mode, this property determines the maximum size of the reusable StringBuilders used by ReusableMessages for formatting purposes.

The default value allows is equal to 2 × (2 × log4j.initialReusableMsgSize + 2) + 2 and allows the StringBuilder to be resized twice by the current JVM resize algorithm.

This property determines the maximum size of the reusable StringBuilders used to format LogEvents.

The Unbox utility class can be used by users to format primitive values without incurring in the boxing allocation cost.

This property specifies the maximum number of primitive arguments to a log message that will be cached and usually does not need to be changed.

If false, Log4j configuration objects like LoggerContexts, Appenders, Loggers, etc. will be instrumented with MBeans and can be remotely monitored and managed.

If true, Log4j’s JMX notifications are sent from a separate background thread, otherwise they are sent from the caller thread.

When true the JndiContextSelector is enabled for the java: protocol. See Web application for more details.

When true, a Log4j JDBC Appender can use JNDI to retrieve a DataSource using the java: protocol.

When true, a Log4j JMS Appender can use JNDI to retrieve the necessary components using the java: protocol.

When true, the Log4j JNDI Lookup can use the java: protocol.

If true, the ThreadContext stack and map are disabled.

If true, the ThreadContext stack is disabled.

If true, the ThreadContext map is disabled.

Fully specified class name of a custom ThreadContextMap implementation class or (since version 2.24.0) one of the predefined constants:

If true uses an InheritableThreadLocal to copy the thread context map to newly created threads.

Note that, as explained in Java’s Executors#privilegedThreadFactory(), when you are dealing with privileged threads, thread context might not get propagated completely.

If set to true selects a garbage-free thread context map implementation.

A comma separated list of URL protocols that may be used to load any kind of configuration source.

To completely prevent accessing the configuration via the Java URL class specify a value of _none.

The fully qualified class name of the AuthorizationProvider implementation to use with http and https URL protocols.

The encoding used in Basic Authentication (cf. RFC 7617).

The password to use in HTTP Basic authentication.

If used in conjunction with log4j2.configurationPasswordDecryptor the contents of this variable are interpreted by the decryptor.

Fully qualified class name of an implementation of PasswordDecryptor to use for the value of the log4j2.configurationPassword property.

If null, the literal value of the password is used.

The username used in HTTP Basic authentication.

The location of the trust store.

The password for the trust store.

The name of a file that contains the password for the trust store.

The name of the environment variable that contains password for the trust store.

The type of trust store.

Name of the KeyManagerFactory implementation to use for the trust store.

If true enables verification of the name of the TLS server.

The location of the private key store.

The password for the private key store.

The name of a file that contains the password for the private key store.

The name of the environment variable that contains the password for the private key store.

The type of private key store. See KeyStore.

Name of the KeyManagerFactory implementation to use for the private key store. See KeyManagerFactory.

Specifies the Clock implementation used to timestamp log events.

This must be the fully qualified class name of the implementation or one of these predefined constants:

Fully qualified class name of a StringMap implementation to use to store context data in log events. The implementation must have:

Fully qualified class name of a ContextDataInjector implementation.

The default implementation uses all implementations of ContextDataProvider registered with ServiceLoader.

Specifies the LogEventFactory implementation to use to create log events.

Specifies the ReliabilityStrategy to adopt in order to prevent loss of log events during a reconfiguration.

The value must be the fully qualified class name of a ReliabilityStrategy implementation or one of these predefined constants:

Number of milliseconds to wait before stopping the old configuration if the AwaitUnconditionally reliability strategy is used. See log4j2.reliabilityStrategy.

If true a shutdown hook will be installed to stop all logger contexts when the system stops.

The fully qualified class name of a ShutdownCallbackRegistry implementation. Integrators can use this to customize the shutdown order of the JVM.

The default implementation executes all shutdown actions in a separate Thread registered through Runtime#addShutdownHook().

Provides a long see to the UUID generator used by the %uuid pattern converter.

Can be used to assure uniqueness of UUIDs generated by multiple JVMs on the same machine.

Fully qualified class name of a MessageFactory implementation that will be used by loggers if no explicit factory was specified.

Fully qualified class name of a FlowMessageFactory implementation to be used by all loggers.

Configures the date & time formatter used for log event instants. The following values are accepted:

Prints a stacktrace to the Status Logger at DEBUG level when the LoggerContext is started.

For debug purposes only.

The list of script languages that are allowed to execute.

The names specified must correspond to those returned by ScriptEngineFactory.getNames().

Fully qualified name of an alternative org.apache.logging.log4j.jul.LevelConverter implementation.

Fully qualified class name of the org.apache.logging.log4j.jul.AbstractLoggerAdapter implementation to use.

This property allows users to choose between two implementations of the logging bridge:

Disables the usage of the Spring Boot Log4j2CloudConfigLoggingSystem.