Fix Javadoc errors to build on jdk 11

Author: joshiste

pom.xml

@@ -127,6 +127,9 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-javadoc-plugin</artifactId>
+                <configuration>
+                    <source>${java.version}</source>
+                </configuration>
                 <executions>
                     <execution>
                         <id>attach-javadocs</id>
@@ -163,6 +166,7 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <configuration>
+                    <parameters>true</parameters>
                     <source>${maven.compiler.source}</source>
                     <target>${maven.compiler.target}</target>
                 </configuration>

spring-boot-admin-client/src/main/java/de/codecentric/boot/admin/client/registration/Application.java

@@ -50,6 +50,10 @@ protected Application(String name,
         this.metadata = new HashMap<>(metadata);
     }
 
+    public static class Builder {
+        //Will be generated by lombok
+    }
+
     public static Builder create(String name) {
         return Application.builder().name(name);
     }

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/server/domain/values/Registration.java

@@ -69,6 +69,10 @@ private Registration(String name,
         this.metadata = new LinkedHashMap<>(metadata);
     }
 
+    public static class Builder {
+        //Will be generated by lombok
+    }
+
     public static Registration.Builder create(String name, String healthUrl) {
         return builder().name(name).healthUrl(healthUrl);
     }
@@ -78,7 +82,7 @@ public static Registration.Builder copyOf(Registration registration) {
     }
 
     public Map<String, String> getMetadata() {
-        return Collections.unmodifiableMap(metadata);
+        return Collections.unmodifiableMap(this.metadata);
     }
 
     /**