如何在运行java jar应用程序时修复“java.lang.NoClassDefFoundError：org / slf4j / LoggerFactory”错误

Question

we are using eclipse+spring tool suite to build java application, we can start the application in eclipse IDE, but if we export as jar with all dependency jars, and run it on linux machine. we always gets error as following:

Exception in thread "main" java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
    at com.ctrip.framework.apollo.demo.api.SimpleApolloConfigDemo.<clinit>(SimpleApolloConfigDemo.java:22)
Caused by: java.lang.ClassNotFoundException: org.slf4j.LoggerFactory
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

here is our POM.xml below:

<?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">
    <parent>
        <artifactId>apollo</artifactId>
        <groupId>com.ctrip.framework.apollo</groupId>
        <version>1.3.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>apollo-demo</artifactId>
    <name>Apollo Demo</name>
    <packaging>jar</packaging>
    <properties>
        <java.version>1.7</java.version>
        <github.path>${project.artifactId}</github.path>
    </properties>
    <dependencies>
        <dependency>
            <groupId>com.ctrip.framework.apollo</groupId>
            <artifactId>apollo-client</artifactId>
            <version>${project.version}</version>
        </dependency>
        <!-- for spring demo -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
        </dependency>
        <!-- for spring boot demo -->
        <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>
    <!-- for refresh scope demo -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-context</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-slf4j-impl</artifactId>
        </dependency>
        <!-- take over jcl -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jcl-over-slf4j</artifactId>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
        </dependency>
        <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-api</artifactId>
             <version>1.7.25</version>
        </dependency>        
    </dependencies>
</project>

2.1 we already included slf4j-log4j12 and slf4j-api as depdency.

2.2 the application can run normally in eclipse IDE window.

2.3 if we export executable jar including all dependencies, and ship jar on linux machine, run the jar file will get the above error.

2.4 we also checked generated jar package on windows with winRAR, the slf4j and log4j* jar package were there, see picture below.

we have struggled this for half day, but did not get any progress. Hope each expert can share with us some light or any suggestions. really appreciated!!!

Answer 1

You need to tell maven to compile the dependencys like this, the jars are compiled but you need the src in youre jar and not the jars in there:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>3.0.0</version>
            <configuration>
            </configuration>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

and dependencys normaly have a <scope>compile</scope> tag, to tell the compile that they are needed at runtime

Answer 2

I've faced a similar problem few days ago, right I add the jar libraries but the core (scripts/classes) of the jar file are no included due some reason I was able to solve that problem by right click on the jar file go to properties and set the class path for the classes of that jar folder.

if you wanna check that the jar file has no class Def inside it explore the jar file from the explorer and double click on any class you'll see a page showing up and says there's no script for this class and it asks you to set the class path.

Another approach I tried which also worked for me is I've imported the same jar files on netbeans and they worked 100%