I've a Spring Boot application where one of the dependencies is using spring and a embedded jetty to start an ad-hoc web server. This causes my spring boot app to start in a jetty instead of a tomcat.
My spring-boot-starter-web:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-websocket</artifactId>
</exclusion>
</exclusions>
</dependency>
The dependencies pom:
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.integration</groupId>
<artifactId>spring-integration-http</artifactId>
</dependency>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-server</artifactId>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-servlet</artifactId>
</dependency>
Is there a possibility to configure the server to use by spring boot explicitly instead of being inferred by the dependency tree?
EDIT
I investigated the issue a little bit further and created a repo to reproduce the issue: github.com/svettwer/spring-server-test
org.eclipse.jetty.websocket:javax-websocket-server-impl causes spring to start with jetty without any other config required.
EDIT 2
The issue is not present anymore in Spring Boot 2.x
EDIT 3
I'll deleted the repo mentioned earlier, but here is the dependency setup that caused the issue:
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>1.5.7.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<version>1.5.7.RELEASE</version>
<scope>test</scope>
</dependency>
<!-- Comment that in to start spring with jetty-->
<dependency>
<groupId>org.eclipse.jetty.websocket</groupId>
<artifactId>javax-websocket-server-impl</artifactId>
<version>9.4.8.v20171121</version>
</dependency>
</dependencies>
Normally, if you have the spring-boot-starter-tomcat on your classpath (through spring-boot-starter-web), it should always select Tomcat since it has priority over other servlet containers. Even if you have the following dependencies, Spring boot will start with Tomcat:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-server</artifactId>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-webapp</artifactId>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-servlet</artifactId>
</dependency>
You can programmatically override the chosen servlet container by registering your own ServletWebServerFactory, for example:
#Bean
public ServletWebServerFactory factory() {
return new TomcatServletWebServerFactory();
}
You can choose the predefined TomcatServletWebServerFactory, JettyServletWebServerFactory or the UndertowServletWebServerFactory.
This guide may help you: https://docs.spring.io/spring-boot/docs/current/reference/html/howto-embedded-web-servers.html
If you run an mvn dependency:tree and search for jetty you might find that you need to exclude it, e.g:
spring-boot-starter-jetty
excluded like in the example:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<!-- Exclude the Tomcat dependency -->
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<!-- Use Jetty instead -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
which is favouring jetty over tomcat - but you get the idea hopefully...
Hope this helps.
I am building a spring-boot application using an alternative to tomcat related stuff (jetty instead of tomcat and hikariCP instead of tomcat-jdbc) and want to exclude them from my dependencies written in pom.xml
I did that for 2 of the packages as shown below -
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jetty</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
<exclusions>
<exclusion>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-jdbc</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>com.zaxxer</groupId>
<artifactId>HikariCP</artifactId>
<version>2.6.0</version>
</dependency>
But there is some dependency which is including tomcat-jdbc as part of it.
Is there a way to debug that and find out which dependency is including tomcat jdbc as part of it?
mvn dependency:tree
If you run mvn dependency:tree, you will see that there are now a number of additional dependencies.
I have created a log4j.properties file, and I have put it in the resources folder as the application.properties file, in this file I have this line : logging.config=log4j.properties which indicated the name of my log4j properties file, but when I run my application I'm getting this error on my console :
Logging system failed to initialize using configuration from 'log4j.properties'
java.io.FileNotFoundException: C:\Users\***\Desktop\CapRecrute\log4j.properties (The system cannot find the file specified)
so I tried to change the logging.config property to src\\main\\resources\\log4j.properties, and then I got another error :
java.lang.IllegalStateException: Could not initialize Logback logging from src\main\resources\log4j.properties ... Caused by: ch.qos.logback.core.LogbackException: Unexpected filename extension of file [file:/C:/Users/Aimad%20MAJDOU/Desktop/CapRecrute/src/main/resources/log4j.properties]. Should be either .groovy or .xml
in my pom file I have this :
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</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>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
</exclusion>
</exclusions>
</dependency>
How can I solve this ?
The simplest thing is to use Spring's Logback. You just need to add these 2 lines to application.properties
logging.level.org.springframework.web=DEBUG
logging.level.org.hibernate=ERROR
and make sure there are no other logging related lines.
If you instead want log4j, then configure so in your pom.xml:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<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>
And then in your paplication.properties:
logging.path=/tmp/logs/
logging.file=/tmp/logs/myapplog.log
logging.config=log4j.properties
Also make sure log4j is in the root of your project (not under resources).
Spring boot is expecting a logback file by default and you have provided log4j configuration. If you add the log4j dependency you should find it works. If you are using maven you can do so like this:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>
Two issues:
Is slf4j-log4j12 exclusion required?
I think that exclusion of spring-boot-starter-logging should be applied to spring-boot-starter.
That's not complete POM. I assume that spring-boot-starter is included, right?
If you remove slf4j-log4j12 exclusion and move spring-boot-starter-logging to spring-boot-starter your file should look like example from documentation.
http://docs.spring.io/spring-boot/docs/current/reference/html/howto-logging.html
<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-tomcat</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j</artifactId>
</dependency>
I have my own slf4j implementation so I want to remove logback from many dependencies, e.g.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>...</version>
<exclusions>
<exclusion>
<artifactId>logback-classic</artifactId>
<groupId>ch.qos.logback</groupId>
</exclusion>
</exclusions>
</dependency>
...
But I find a quick way by adding it as test scope:
<dependency>
<artifactId>logback-classic</artifactId>
<groupId>ch.qos.logback</groupId>
<version>...</version>
<scope>test</scope>
</dependency>
Is this a good practice in maven?
I can see how test scope does the trick, but I would personally oppose from such hacks. If your team loose discipline and start incorporating hacks into your application just to save few lines of code, your application will be unmaintainable pretty soon.
You also shouldn't specify versions of spring managed dependencies. You should just define Spring boot version in parent section of your pom. You can find matrix of spring managed dependencies in spring-boot-dependencies file.
I would suggest excluding spring-boot-starter-logging instead of logback directly. So if you are using log4j2 (hopefully you are not planning to use log4j anymore), just do this:
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.3.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</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>
It appears Springboot autoconfigures itself to use Logback with Tomcat. I would like to disable this and use the one I provide in my classpath.
The error message below.
LoggerFactory is not a Logback LoggerContext but Logback is on the
classpath. Either remove Logback or the competing implementation
(class org.slf4j.impl.SimpleLoggerFactory) Object of class
[org.slf4j.impl.SimpleLoggerFactory] must be an instance of class
ch.qos.logback.classic.LoggerContext
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<artifactId>spring-boot-starter-parent</artifactId>
<groupId>org.springframework.boot</groupId>
<version>1.0.1.RELEASE</version>
</parent>
<groupId>com.fe</groupId>
<artifactId>cloudapp</artifactId>
<version>1.0.0</version>
<name>Withinet-PaaS</name>
<description>Develop your web applications in on our infrastructure and we will worry about administration and scalability of your app.</description>
<properties>
<java.version>1.7</java.version>
<guava.version>16.0.1</guava.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
</properties>
<dependencies>
<dependency>
<groupId>com.sun.jersey</groupId>
<artifactId>jersey-client</artifactId>
<version>1.8</version>
</dependency>
<dependency>
<groupId>com.withinet.cloudapp</groupId>
<artifactId>slave</artifactId>
<version>1.0.0</version>
</dependency>
<dependency>
<groupId>org.apache.wicket</groupId>
<artifactId>wicket-core</artifactId>
<version>6.15.0</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.3.0.Final</version>
</dependency>
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.2.4</version>
</dependency>
<!-- Spring Boot -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- Hibernate validator -->
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>1.1.0.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator-annotation-processor</artifactId>
<version>4.1.0.Final</version>
</dependency>
<!-- Guava -->
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>${guava.version}</version>
</dependency>
<!-- Java EE -->
<dependency>
<groupId>javax.inject</groupId>
<artifactId>javax.inject</artifactId>
<version>1</version>
</dependency>
<!-- Search -->
<dependency>
<groupId>org.apache.lucene</groupId>
<artifactId>lucene-queryparser</artifactId>
<version>4.8.0</version>
</dependency>
<!-- Security
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<plugins>
<!-- Spring Boot Maven -->
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<mainClass>com.withinet.cloud.Application</mainClass>
<layout>JAR</layout>
</configuration>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
Add exclusion to both the spring-boot-starter and spring-boot-starter-web to resolve the conflict.
<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-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
To add a better, more generic solution in Gradle (all instances will be excluded):
configurations {
all*.exclude module : 'spring-boot-starter-logging'
}
From https://docs.gradle.org/current/userguide/dependency_management.html
To add a solution in gradle.
dependencies {
compile ('org.springframework.boot:spring-boot-starter') {
exclude module : 'spring-boot-starter-logging'
}
compile ('org.springframework.boot:spring-boot-starter-web') {
exclude module : 'spring-boot-starter-logging'
}
}
Correct way to exclude default logging, and configure log4j for logging.
<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>
Refer Spring Logging - How To.
In gradle, I needed to do this with several other dependencies:
configurations {
all*.exclude module : 'spring-boot-starter-logging'
all*.exclude module : 'logback-classic'
}
I found that excluding the full spring-boot-starter-logging module is not necessary. All that is needed is to exclude the org.slf4j:slf4j-log4j12 module.
Adding this to a Gradle build file will resolve the issue:
configurations {
runtime.exclude group: "org.slf4j", module: "slf4j-log4j12"
compile.exclude group: "org.slf4j", module: "slf4j-log4j12"
}
See this other StackOverflow answer for more details.
For gradle,
You can see this solution at: http://www.idanfridman.com/how-to-exclude-libraries-from-dependcies-using-gradle/
Just need add exclude in configurations:
configurations {
providedRuntime
compile.exclude(group: 'ch.qos.logback')
}
I do like this to solve my problem
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j</artifactId>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
</exclusion>
</exclusions>
</dependency>
Find spring-boot-starter-test in your pom.xml and modify it as follows:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<exclusions>
<exclusion>
<artifactId>commons-logging</artifactId>
<groupId>commons-logging</groupId>
</exclusion>
</exclusions>
<scope>test</scope>
</dependency>
It fixed error like:
_Caused by: java.lang.IllegalArgumentException:_ **LoggerFactory** is not a **Logback LoggerContext** but *Logback* is on the classpath.
Either remove **Logback** or the competing implementation
(_class org.apache.logging.slf4j.Log4jLoggerFactory_
loaded from file:
**${M2_HOME}/repository/org/apache/logging/log4j/log4j-slf4j-impl/2.6.2/log4j-slf4j-impl-2.6.2.jar**).
If you are using WebLogic you will need to add **'org.slf4j'** to prefer-application-packages in WEB-INF/weblogic.xml: **org.apache.logging.slf4j.Log4jLoggerFactory**
It might help if you say what your preferred logger is exactly, and what you did to try and install it. Anyway, Spring Boot tries to work with whatever is in the classpath, so if you don't want logback, take it off the classpath. There are instructions for log4j in the docs, but the same thing would apply to other supported logging systems (anything slf4j, log4j or java util).
Following works for me
<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>
Same problem for me.
If you are using log4j2
In the Spring boot 2.4.0
I resolve below,
<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>
<exclusions>
<exclusion>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId> <-- exclude this artifactId
</exclusion>
</exclusions>
</dependency>
After, Maven Build > Clean > Run
Work for me.
I resolved my problem through this below:
compile('org.mybatis.spring.boot:mybatis-spring-boot-starter:1.3.0'){
exclude module: 'log4j-slf4j-impl'
exclude module: 'logback-classic'
}
compile('org.springframework.boot:spring-boot-starter-web'){
exclude module: 'log4j-slf4j-impl'
exclude module: 'logback-classic'
}
In my case, it was only required to exclude the spring-boot-starter-logging artifact from the spring-boot-starter-security one.
This is in a newly generated spring boot 2.2.6.RELEASE project including the following dependencies:
spring-boot-starter-security
spring-boot-starter-validation
spring-boot-starter-web
spring-boot-starter-test
I found out by running mvn dependency:tree and looking for ch.qos.logback.
The spring boot related <dependencies> in my pom.xml looks like this:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</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>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
This worked for me just fine
configurations {
all*.exclude module : 'spring-boot-starter-logging'
}
But it wouldn't work out for maven users. All my dependencies was in libs.gradle and I didn't want them in other files. So this problem was solved by adding exclude module : 'spring-boot-starter-logging in spring-boot-starter-data-jpa, spring-boot-starter-test and in practically everything with boot word.
UPDATE
New project of mine needed an update, turns out spring-boot-starter-test 1.5 and older didn't have spring-boot-starter-logging. 2.0 has it
Add this in your build.gradle
configurations.all {
exclude group: 'org.springframework.boot', module: 'spring-boot-starter-tomcat'
exclude group: 'org.springframework.boot', module: 'spring-boot-starter-logging'
exclude group: 'org.springframework.boot', module: 'logback-classic'
}
Using Gradle & Lombok, here is the simplest configuration for Log4j2 that worked for me using the latest Spring Boot (2.4.1 at this time) :
build.gradle (partial)
configurations {
compileOnly { extendsFrom annotationProcessor }
compile.exclude module: 'spring-boot-starter-logging'
}
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation 'org.springframework.boot:spring-boot-starter-security'
implementation 'org.springframework.boot:spring-boot-starter-web-services'
implementation 'org.springframework.boot:spring-boot-starter-log4j2'
compileOnly 'org.projectlombok:lombok'
// (*** other dependencies ***)
annotationProcessor 'org.projectlombok:lombok'
testImplementation 'org.springframework.boot:spring-boot-starter-test'
testImplementation 'org.springframework.security:spring-security-test'
}
I noticed you will get errors if you include spring-bbot-starter-log4j2 as a compileOnly dependency instead of as an implementation.
Just annotate your classes with #Log4j2 (or #Slf4j) and lombok will make available a log variable you can use for logging.
As usual, provide a log4j2.xml configuration file in your /src/main/resources folder.
If this error occurred in SpringBoot when you are trying to use log4j2 then
do these steps:
Remove the jar from while packeging by adding this "excludeGroupIds log4j-slf4j-impl /excludeGroupIds"
Find out the which library is depends on "logback-classic" by using command "mvn dependecy:tree"
Wherever you find it exclude it from the dependency.
This error occurred because logback override the log4j2 changes. SO if you want to use log4j2 then you have to remove logback library and dependencies.
Hope this will help someone.
Just add logback.xml configuration in your classpath and add all your configuration with root appender added. Once the Spring boot completes the bean loading, it will start logging based on your configuration.
To add an exclusion for logback from Netbeans IDE
Access the >Projects explorer section for your project
Proceed to >Dependencies as displayed below
Trace 'spring-boot-starter-logging-X.X.X.jar'
Right click on the jar and select Exclude Dependency as shown below. This excludes the logback jar on the pom.xml like this;
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
In my case below exclusion works!!
<dependency>
<groupId>com.xyz.util</groupId>
<artifactId>xyz-web-util</artifactId>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
</exclusion>
</exclusions>
</dependency>
Adding exclusions was not enough for me. I had to provide a fake jar:
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<scope>system</scope>
<systemPath>${project.basedir}/empty.jar</systemPath>
</dependency>
The reason is, spring boot comes with logback as its default log configuration whereas camel uses log4j. Thats the reason of conflict. You have two options, either remove logback from spring boot as mentioned in above answers or remove log4j from camel.
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-spring-boot-starter</artifactId>
<version>${camel.version}</version>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
</exclusion>
</exclusions>
</dependency>
Disable spring boot starter logging
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
Disable LogBack OR Log4j From Spring Boot Starter
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-to-slf4j</artifactId>
</exclusion>
<exclusion>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
</exclusion>
</exclusions>
</dependency>