How to obfuscate WAR with maven plugin for Proguard?

Question

How do I obfuscate a WAR using proguard? I have one WAR which contains multiple dependencies as JARs inside and I want to obfuscate only my codebase, by filtering by package name (leaving the rest of dependencies intact).

I'm getting thousands of warnings. How do I even do this? Am I supposed to skim through every single one of them and check if they have to be looked at / suppressed? am I missing a piece of configuration?

why am I getting warnings, shouldn't all dependencies be there?

java version is 8

<plugin>
    <groupId>com.github.wvengen</groupId>
    <artifactId>proguard-maven-plugin</artifactId>
    <version>${proguard.maven.plugin.version}</version>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>proguard</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <proguardVersion>${proguard.version}</proguardVersion>
        <injar>${project.build.finalName}.war</injar>
        <outjar>${project.build.finalName}.obfuscated.war</outjar>
        <obfuscate>true</obfuscate>
        <options>
            <option>-dontnote !my.package**</option>

            <option>-dontskipnonpubliclibraryclassmembers</option>
            <option>-dontshrink</option>
            <option>-dontoptimize</option>

            <option>-adaptclassstrings</option>
            <!-- This option will save all original annotations and etc. Otherwise all we be removed from files.-->
            <option>-keepattributes
                Signature,
                *Annotation*
            </option>

            <option>-ignorewarnings</option>
            <!-- This option will save all original class files (without obfuscate) in service package-->
            <!-- <option>-keep class com.slm.proguard.example.spring.boot.service { *; }</option>-->
            <!-- This option will save all original interfaces files (without obfuscate) in all packages.-->
            <option>-keep interface !my.package** { *; }</option>
            <option>-keep class !my.package** { *; }</option>
        </options>
        <injarNotExistsSkip>true</injarNotExistsSkip>
        <libs>
            <!--Put here your libraries if required-->
            <lib>${java.home}/lib/rt.jar</lib>
            <lib>${java.home}/lib/jce.jar</lib>
        </libs>
    </configuration>
    <dependencies>
        <dependency>
            <groupId>com.guardsquare</groupId>
            <artifactId>proguard-base</artifactId>
            <version>${proguard.version}</version>
        </dependency>
    </dependencies>
</plugin>

Answer 1

You have to obfuscate the JAR before building the WAR file. The proguard plugin should be only applied to the .war if it contains classes in the WEB-INF/classes directory.