I started from the most simple Java Maven generated project and added a class that should be obfuscated
There is no obfuscation after
mvn clean install
I attached an archive with the whole Maven / Intellij project
Google Drive zip with Hello World project
the pom looks like that
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<id>assembly</id>
<goals>
<goal>single</goal>
</goals>
<phase>package</phase>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>com.github.wvengen</groupId>
<artifactId>proguard-maven-plugin</artifactId>
<version>2.0.8</version>
<executions>
<execution>
<phase>package</phase>
<goals><goal>proguard</goal></goals>
<configuration>
<injar>${project.build.finalName}-jar-with-dependencies.jar</injar> <!-- make sure to obfuscate the jar with dependencies -->
<proguardVersion>5.2</proguardVersion>
<options>
<option>-allowaccessmodification</option>
<option>-dontoptimize</option>
<option>-dontshrink</option>
<option>-dontnote</option>
<option>-dontwarn</option> <!-- added option to ignore com.sun missing classes -->
<option>-keepattributes Signature</option>
<option>-keep class com.mycompany.MyPlugin { *; }</option>
</options>
<libs>
<lib>${java.home}/lib/rt.jar</lib>
</libs>
<dependencies>
<dependency>
<groupId>net.sf.proguard</groupId>
<artifactId>proguard-base</artifactId>
<version>5.2</version>
<scope>runtime</scope>
</dependency>
</dependencies>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</pluginManagement>