Parameterized Map not parameterized after proguard obfuscation

Question

I am writing a plugin api for my application. The problem now is, that anything in my Maven Proguard config messed up the parameterized Maps, Lists and other parameterized objects.

So I have this code:

public final Map<String, PermissionGroup> getPermissionGroups() {
    return Vars.PERMGROUPS;
}

Vars.PERMGROUPS is this:

public static final Map<String, PermissionGroup> PERMGROUPS = new HashMap<>();

So now, when I call getPermissionGroups I get a Map without parameters.

pom.xml

...
        <plugin>
            <groupId>com.github.wvengen</groupId>
            <artifactId>proguard-maven-plugin</artifactId>
            <version>2.0.11</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>proguard</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <obfuscate>true</obfuscate>
                <injar>${project.build.finalName}.jar</injar>
                <outjar>${project.build.finalName}-final.jar</outjar>
                <includeDependency>true</includeDependency>
                <options>
                    <option>-keep public class my.package.Main { public static void main(java.lang.String[]); }</option>
                    <option>-keep public class my.package.plugins.** { *; }</option>
                    <option>-keep public class my.package.wrapper.** { *; }</option>
                    <option>-dontusemixedcaseclassnames</option>
                    <option>-dontskipnonpubliclibraryclasses</option>
                    <option>-verbose</option>
                    <option>-obfuscationdictionary dict.txt</option>
                    <option>-classobfuscationdictionary dict.txt</option>
                    <option>-packageobfuscationdictionary dict.txt</option>
                </options>
                <libs>
                    <lib>${java.home}/lib/rt.jar</lib>
                    <lib>${java.home}/lib/jce.jar</lib>
                </libs>
                <assembly>
                    <inclusions>
                        ...
                    </inclusions>
                </assembly>
                <archive>
                    <manifest>
                        <mainClass>my.package.Main</mainClass>
                    </manifest>
                </archive>
            </configuration>
            <dependencies>
                <dependency>
                    <groupId>net.sf.proguard</groupId>
                    <artifactId>proguard-base</artifactId>
                    <version>4.11</version>
                    <scope>runtime</scope>
                </dependency>
            </dependencies>
        </plugin>
...

there are just 20000 random strings in dict.txt.

Answer 1

According to How do you stop Proguard from removing type parameters?. I just had to add -keepattributes Signature