I'm new to maven and am having trouble adding a dependency (sl4j). I was given this project which was apparently converted to maven from ant. Btw, a clean install doesn't work. Here's the pom.xml:
<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>
    <groupId>com.xxx.tools</groupId>
    <artifactId>someName</artifactId>
    <version>1.0</version>
    <name>A Name</name>
    <description>Description</description>
    <properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.1.0</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <transformers>
                                <transformer
                                    implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>com.MyClient</mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>
It give the following message on a clean install:
`ERROR] Failed to execute goal org.apache.maven.plugins:maven-shade-plugin:3.1.0:shade (default) on project xxxx: Execution default of goal org.apache.maven.plugins:maven-shade-plugin:3.1.0:shade failed: Plugin org.apache.maven.plugins:maven-shade-plugin:3.1.0 or one of its dependencies could not be resolved: Failed to collect dependencies at org.apache.maven.plugins:maven-shade-plugin:jar:3.1.0 -> org.apache.maven:maven-plugin-api:jar:3.0 -> org.sonatype.sisu:sisu-inject-plexus:jar:1.4.2 -> org.codehaus.plexus:plexus-component-annotations:jar:1.6: Failed to read artifact descriptor for org.codehaus.plexus:plexus-component-`annotations:jar:1.6: Could not transfer artifact org.codehaus.plexus:plexus-component-annotations:pom:1.6 from/to central (https://repo.maven.apache.org/maven2): sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target -> [Help
 
    
 
     
     
     
     
    


