Disabling Log4J Output in Java

Question

How can one quickly turn off all Log4J output using a log4j.properties file?

score 129 · Accepted Answer · answered Feb 21 '09 at 02:22

129

Set level to OFF (instead of DEBUG, INFO, ....)

answered Feb 21 '09 at 02:22

Edwin

2,671
2
19
24

score 86 · Answer 2 · answered Jul 18 '11 at 17:42

86

If you want to turn off logging programmatically then use

List<Logger> loggers = Collections.<Logger>list(LogManager.getCurrentLoggers());
loggers.add(LogManager.getRootLogger());
for ( Logger logger : loggers ) {
    logger.setLevel(Level.OFF);
}

answered Jul 18 '11 at 17:42

Andrew Gilmartin

1,776
12
12

6

He specified "using a log4j.properties file" anyway it is very useful. – Jaime Hablutzel Jul 18 '11 at 17:53
And how do you revert the loggers to the previous setting (programmatically)? – Sachin Sharma Apr 04 '17 at 11:31
No magic, just simple programming. Store the current level in a Map in long-lived context and then revert by iterating over the entry set calling e.getKey().setLevel(e.getValue()) – Andrew Gilmartin Apr 07 '17 at 20:40
This doesnt work now as LogManager does not exist – Joehot200 Oct 18 '21 at 14:36

score 52 · Answer 3 · answered Feb 25 '09 at 09:42

52

 log4j.rootLogger=OFF

answered Feb 25 '09 at 09:42

flybywire

261,858
191
397
503

score 15 · Answer 4 · answered Feb 21 '09 at 12:07

15

You can change the level to OFF which should get rid of all logging. According to the log4j website, valid levels in order of importance are TRACE, DEBUG, INFO, WARN, ERROR, FATAL. There is one undocumented level called OFF which is a higher level than FATAL, and turns off all logging.

You can also create an extra root logger to log nothing (level OFF), so that you can switch root loggers easily. Here's a post to get you started on that.

You might also want to read the Log4J FAQ, because I think turning off all logging may not help. It will certainly not speed up your app that much, because logging code is executed anyway, up to the point where log4j decides that it doesn't need to log this entry.

answered Feb 21 '09 at 12:07

Rolf

7,098
5
38
55

And underneath TRACE is the "level" ALL, what's kind of the opposite. Secondly, it could be faster if the programm does something like "if(logger.isDebugEnabled()) logger.debug(...)" – Tim Büthe Feb 25 '09 at 10:48
The OP doesn't mention performance as the reason for wanting to turn off all logging. When I've needed to do this, it's because many libraries suffer from a kind of logging dysentery, which produces no useful information and I want a short-hand way of dealing with it. – Mark Slater Apr 07 '16 at 09:08

score 10 · Answer 5 · edited Mar 10 '20 at 18:11

10

In addition, it is also possible to turn logging off programmatically:

Logger.getRootLogger().setLevel(Level.OFF);

Or

Logger.getRootLogger().removeAllAppenders();
Logger.getRootLogger().addAppender(new NullAppender());

These use imports:

import org.apache.log4j.Logger;
import org.apache.log4j.Level;
import org.apache.log4j.NullAppender;

edited Mar 10 '20 at 18:11

Cory Klein

51,188
43
183
243

answered Sep 05 '17 at 17:08

Maytham Fahmi

31,138
14
118
137

1

This is the best solution for standalone apps that shouldn't log anything. – basZero Feb 09 '18 at 10:57

score 5 · Answer 6 · answered Aug 18 '16 at 09:12

Change level to what you want. (I am using Log4j2, version 2.6.2). This is simplest way, change to <Root level="off">

For example: File log4j2.xml
Development environment

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
        </Console>
        <Console name="SimpleConsole" target="SYSTEM_OUT">
            <PatternLayout pattern="%msg%n"/>
        </Console>
    </Appenders>
    <Loggers>
        <Root level="error">
            <AppenderRef ref="Console"/>
        </Root>
    </Loggers>
    <Loggers>
        <Root level="info">
            <AppenderRef ref="SimpleConsole"/>
        </Root>
    </Loggers>
</Configuration>

Production environment

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
        </Console>
        <Console name="SimpleConsole" target="SYSTEM_OUT">
            <PatternLayout pattern="%msg%n"/>
        </Console>
    </Appenders>
    <Loggers>
        <Root level="off">
            <AppenderRef ref="Console"/>
        </Root>
    </Loggers>
    <Loggers>
        <Root level="off">
            <AppenderRef ref="SimpleConsole"/>
        </Root>
    </Loggers>
</Configuration>

Disabling Log4J Output in Java

6 Answers6

Linked

Related