Error: The same input jar [C:\Program Files\Java\jdk1.8.0_281\lib\tools.jar] is specified twice.

[turnglight]

exec: mvn clean compile package -DskipTests=true
Error: The same input jar [C:\Program Files\Java\jdk1.8.0_281\lib\tools.jar] is specified twice.

<plugin>
				<groupId>com.github.wvengen</groupId>
				<artifactId>proguard-maven-plugin</artifactId>
				<version>2.0.14</version>
				<executions>
					<execution>
						<phase>package</phase>
						<goals>
							<goal>proguard</goal>
						</goals>
					</execution>
				</executions>

				<configuration>
					<proguardVersion>6.0.2</proguardVersion>
					<obfuscate>true</obfuscate>
					<attachArtifactClassifier>pg</attachArtifactClassifier>
					<options>
						<option>-target 1.8</option>
						<option>-dontshrink</option>
						<option>-dontoptimize</option>
						<option>-dontskipnonpubliclibraryclasses</option>
						<option>-dontskipnonpubliclibraryclassmembers</option>
						<option>-allowaccessmodification</option>
						<option>-useuniqueclassmembernames</option>
						<option>-adaptclassstrings</option>
						<option>-dontusemixedcaseclassnames</option><option>-keeppackagenames</option>
						<option>-keepparameternames</option>
						<option>-keepattributes
							Exceptions,InnerClasses,Signature,Deprecated,SourceFile,LineNumberTable,LocalVariable*Table,*Annotation*,Synthetic,EnclosingMethod,LocalVariableTable,LocalVariableTypeTable,MethodParameters
						</option>
						<option>
							-keepclassmembers public class *{void set*(***);*** get*();}
						</option>
						<option>
							-keepclasseswithmembers public class * { public static void main(java.lang.String[]);}
						</option>
						<option>-keepclassmembers enum * { *; }</option>
						<option>-keep class com.sf.lbs.** { *; }</option>
						<option>-dontwarn **</option>
					</options>
					<libs>
						<lib>${java.home}/lib/rt.jar</lib>
						<lib>${java.home}/lib/jsse.jar</lib>
					</libs>

					<inFilter>com/sf/lbs/**</inFilter>
					<injar>classes</injar>
					<injar>${project.build.finalName}.jar</injar>
					<outjar>${project.build.finalName}-pg.jar</outjar>
					<outputDirectory>${project.build.directory}</outputDirectory>
				</configuration>
				<dependencies>
					<dependency>
						<groupId>net.sf.proguard</groupId>
						<artifactId>proguard-base</artifactId>
						<version>6.0.2</version>
						<scope>runtime</scope>
					</dependency>
				</dependencies>
			</plugin>

[lasselindqvist]

I will not be supporting any Java 8 issues here, but if you have fix for this it can be merged.