Fix problems with deploy

Use ManifestResourceTransformer instead of jar plugin for agent jar
to set manifest entries, as there are problems when executing deploy
otherwise which are related to jar being executed multiple times:

You have to use a classifier to attach supplemental artifacts to the
project instead of replacing them.

Signed-off-by: Felix Barnsteiner <[email protected]>

Author: felixbarny

elastic-apm-agent/pom.xml

@@ -67,6 +67,16 @@
                                 <transformer implementation="org.apache.maven.plugins.shade.resource.ApacheNoticeResourceTransformer">
                                     <addHeader>false</addHeader>
                                 </transformer>
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                    <manifestEntries>
+                                        <Premain-Class>${elastic.apm.agent}</Premain-Class>
+                                        <Agent-Class>${elastic.apm.agent}</Agent-Class>
+                                        <Can-Redefine-Classes>true</Can-Redefine-Classes>
+                                        <Can-Retransform-Classes>true</Can-Retransform-Classes>
+                                        <Can-Set-Native-Method-Prefix>true</Can-Set-Native-Method-Prefix>
+                                        <Automatic-Module-Name>${project.groupId}.agent</Automatic-Module-Name>
+                                    </manifestEntries>
+                                </transformer>
                             </transformers>
                         </configuration>
                     </execution>
@@ -91,24 +101,6 @@
                     </execution>
                 </executions>
             </plugin>
-            <!-- Specify agent manifest headers. -->
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-jar-plugin</artifactId>
-                <version>${version.plugin.jar}</version>
-                <configuration>
-                    <archive>
-                        <manifestEntries>
-                            <Premain-Class>${elastic.apm.agent}</Premain-Class>
-                            <Agent-Class>${elastic.apm.agent}</Agent-Class>
-                            <Can-Redefine-Classes>true</Can-Redefine-Classes>
-                            <Can-Retransform-Classes>true</Can-Retransform-Classes>
-                            <Can-Set-Native-Method-Prefix>true</Can-Set-Native-Method-Prefix>
-                            <Automatic-Module-Name>${project.groupId}.agent</Automatic-Module-Name>
-                        </manifestEntries>
-                    </archive>
-                </configuration>
-            </plugin>
         </plugins>
     </build>