We Keep Coding

Log4j does literally nothing?

My configuration file is path of the class path. At least I thought it is. I placed the log4j.properties file in the resources folder and log4j does nothing with it. Even if I delete it, no error occurs.
As anyone can see I'm using maven
Content of LoggerTest:
package com.dersimi.stella.logger;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
public class LoggerTest {
public static void main(String[] args) {
System.out.println("xxx");
Logger logger = LogManager.getLogger(LoggerTest.class);
logger.info("Hello this is an info message");
System.out.println("xxx");
}
}
Program output:
xxx
xxx
Content of log4j.properties:
log4j.rootLogger=INFO, console
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.Threshold=INFO
log4j.appender.console.Target=System.out
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.conversionPattern=%d{yyyy-MM-dd HH:mm:ss,SSS} %-5p - %m%n
In pom.xml is nothing out of the ordinary, just the dependency org.apache.logging.log4j log4j-core 2.17.2, compiler source target is 16, no plugins

The main problem is that you are trying to use log4j (the first one) configurations for log4j2.
In first place make sure you have the following dependencies:
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.17.0</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.17.0</version>
</dependency>
Second, have a file named log4j2.properties with a content like this:
status = warn
appender.console.type = Console
appender.console.name = LogToConsole
appender.console.layout.type = PatternLayout
appender.console.layout.pattern = [%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %c{1} - %msg%n
rootLogger.level = info
rootLogger.appenderRef.stdout.ref = LogToConsole
Reference: https://mkyong.com/logging/log4j2-properties-example/

Logging : Log4j2 Implementation using log4j2.properties file in Spring Boot

Logging is working fine if i specify
'logging.config = src/main/resources/log4j2.properties'
in my application.properties file.
Is there any other work around where spring boot automatically detects log4j2.properties and doesnot require to specify 'logging.config = src/main/resources/log4j2.properties' inside application.properties file..?
Spring Boot automatically detects log4j2.xml, log4j2.json files in classpath, but not in case log4j2.properties file, in my case
my pom.xml:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>
log4j2.properties:
name=PropertiesConfig
appenders = console, file
appender.console.type = Console
appender.console.name = ConsoleAppender
appender.console.layout.type = PatternLayout
appender.console.layout.pattern = %d{MM:dd HH:mm:ss.SSS} [%t]
[%level] [%logger{36}] - %msg%n
appender.file.type = File
appender.file.name = FileAppender
appender.file.fileName=/home/ubuntu/application.log
appender.file.layout.type=PatternLayout
appender.file.layout.pattern= %d{MM:dd HH:mm:ss.SSS} [%t] [%level]
[%logger{36}] - %msg%n
loggers=file
logger.file.name=com.project
logger.file.level = debug
logger.file.appenderRefs = file
logger.file.appenderRef.file.ref = FileAppender
rootLogger.level = debug
rootLogger.appenderRefs = stdout
rootLogger.appenderRef.stdout.ref = ConsoleAppender
Note : Spring boot version i am using is 2.1.3.RELEASE
Reference : https://docs.spring.io/spring-boot/docs/current/reference/html/howto-logging.html

I am not aware that Spring Boot modifies the logic Log4j 2 uses to locate configuration files. In fact, I have been working on a Spring Boot service that was using a log4j2.yml. I replaced that with a log4j2.properties and it worked fine. Log4j's normal discovery process finds it on the class path.
I am actually surprised that specifying logging.config=src/main/resources/log4j2.properties worked for you as a Spring Boot jar wouldn't normally have the "src" directory in it.

also can use this way:
java -Dlog4j.configurationFile=log4j2.xml -jar xxxx-app.jar
Reference:
https://logging.apache.org/log4j/2.x/manual/configuration.html

log4j does not create a log file in the system

I am creating a Spring Boot Application in STS (Spring Tool Suite).
The problem occurs when trying to log using log4j. It does not create the log file in the system, though it does log on the console. I tried various methods given in the forum(including checking case-sensitivity, , but I think I am going wrong somewhere. An elaborate response would be really helpful.
I have a dependency in the pom.xml file for the log4j jar:-
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
In my log4j.properties file, I am trying to have logs in console as well as a file
# Root logger option
log4j.rootLogger=ALL, stdout, file
# Redirect log messages to console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.conversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
# Redirect log messages to a log file
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=C:\\log4j.log
log4j.appender.file.ImmediateFlush=true
log4j.appender.file.MaxFileSize=5MB
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
#log4j.appender.FILE.layout.conversionPattern=%m%n
log4j.appender.file.layout.conversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
Java controller where I want to log (IndexController.java)
package com.project.Controller;
import org.apache.log4j.Logger;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
#Controller
public class IndexController {
final static Logger logger = Logger.getLogger(IndexController.class.getName());
#RequestMapping("/")
String index(Model model) {
logger.info("in index");
return "index";
}
}
Please comment if you need any further details. Thanks

Create a dependency for spring-boot-starter-log4j and exclude spring-boot-starter-logging in your pom.xml.Make the following entry in your pom.xml:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j</artifactId>
</dependency>
This should create the log file and log the details.

mongodb driver - how to hide debug logging with log4j?

Mongo java driver is verbose since v3.x.x, it's not very optimal to store a log of logs like this. Would like to hide some of them.
Here are my dependencies (maven / pom.xml)
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongo-java-driver</artifactId>
<version>3.0.1</version>
</dependency>
<!-- LOGS -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.5</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>jcl-over-slf4j</artifactId>
<version>1.7.5</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>jul-to-slf4j</artifactId>
<version>1.7.5</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.5</version>
</dependency>
I want to hide mongo java driver logs :
2015-05-16 10:43:22 023 DEBUG command:56 - Sending command {count : BsonString{value='skydatas'}} to database rizze on connection [connectionId{localValue:2, serverValue:9}] to server 127.0.0.1:27017
2015-05-16 10:43:22 041 DEBUG command:56 - Command execution completed
2015-05-16 10:43:22 042 DEBUG command:56 - Sending command {count : BsonString{value='skydatas'}} to database rizze on connection [connectionId{localValue:2, serverValue:9}] to server 127.0.0.1:27017
2015-05-16 10:43:22 060 DEBUG command:56 - Command execution completed
2015-05-16T10:49:34.448Z DEBUG Checking status of 127.0.0.1:27017 | | cluster:56
2015-05-16T10:49:34.452Z DEBUG Updating cluster description to {type=STANDALONE, servers=[{address=127.0.0.1:27017, type=STANDALONE, roundTripTime=1,3 ms, state=CONNECTED}] | | cluster:56
Thanks

You should be able to do this from your log4j configuration file.
The first thing I would do is temporarily add the fully-qualified class name to your log4j appender format (%C if you're using a formatter based on PatternLayout). That gives you the package and class names of the source of the logging statements you want to exclude.
Then follow the example from the log4j manual to specifically raise the logging level of the packages/classes you don't want to see (search the page for text from the snippet below to find it on the page for more context):
# Print only messages of level WARN or above in the package com.foo.
log4j.logger.com.foo=WARN
Don't forget to take the %C out of your pattern when you've excluded all the packages you don't want to see.

Here is a log4j configuration, I'm using with log4j:
# Log4J logger file
log = ./log4j
log4j.rootLogger = WARN, CONSOLE
log4j.logger.com.rizze.db=INFO
# Direct log messages to stdout
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.Target=System.out
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss SSS} %-5p %m / %c{1}:%L %n
What is doing this work around
- show Logs with level >= INFO for package com.rizze.db
- show others Logs with level >= WARN

it is work for me.
add this line to you log4j configuration to fix this problem.
log4j.logger.org.mongodb.driver=ERROR

slf4j + log4j shows all logs except mine

I am using slf4j with log4j, and for some reason all the logs are showing except the logs that I write in my code - Spring logs, Hibernate logs, you name it logs are showing and in the level configured in log4j.properties. My logs however, are not showing.
Maven dependencies:
log4j
log4j
1.2.17
test
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${org.slf4j.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>${org.slf4j.version}</version>
<scope>test</scope>
</dependency>
When running with -Dlog4j.debug I see that my log4j.propertes file is being used
log4j: Trying to find [log4j.xml] using context classloader sun.misc.Launcher$AppClassLoader#11a5ee7c.
log4j: Trying to find [log4j.xml] using sun.misc.Launcher$AppClassLoader#11a5ee7c class loader.
log4j: Trying to find [log4j.xml] using ClassLoader.getSystemResource().
log4j: Trying to find [log4j.properties] using context classloader sun.misc.Launcher$AppClassLoader#11a5ee7c.
log4j: Using URL [ile:/C:/x/y/myProject/target/test-classes/log4j.properties] for automatic log4j configuration.
log4j: Reading configuration from URL file:/C:/x/y/myProject/target/test-classes/log4j.properties
And I'm using the following log code:
private static final Logger LOG = LoggerFactory.getLogger(MyClass.class);
LOG.warn("Very informative message");
My log4j.properties file:
# Define the root logger to the system property "hbase.root.logger".
log4j.rootLogger=DEBUG, console
# Logging Threshold
log4j.threshhold=ALL
#
# console appender
# Add "console" to rootLogger above if you want to use this
#
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.target=System.out
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=%d %-5p [%t] %C{2}(%L): %m%n
Adding a specific line for my logger doesn't help as well
log4j.logger.com.my.path=DEBUG, console
And I can see that it is being recognized:
Parsing for [com.my.path] with value=[DEBUG, console].
log4j: Level token is [DEBUG].
log4j: Category com.my.path set to DEBUG
But still nothing is being logged.

Replace this line:
log4j.rootLogger=DEBUG, console
with this:
log4j.rootLogger = ALL, Console
Delete these two lines:
log4j.threshhold=ALL
log4j.appender.console.target=System.out
Not sure what all of that pattern is doing, so I would replace this line
log4j.appender.console.layout.ConversionPattern=%d %-5p [%t] %C{2}(%L): %m%n
with this:
log4j.appender.Console.layout.conversionPattern=%m%n
Then do this:
final static Logger logger = Logger.getLogger(MyClassName.class);
logger.info("This is info");