Minor Java doc fixes

src/main/java/org/wildfly/installationmanager/ChannelChange.java

@@ -37,8 +37,8 @@ public enum Status {ADDED, REMOVED, MODIFIED}
      * constructs a channel change. At least one of the channels has to be non-null.
      * If both {@code oldChannel} and {@code newChannel} are provided their names have to be the same
      *
-     * @param oldChannel
-     * @param newChannel
+     * @param oldChannel - Old channel version
+     * @param newChannel - New channel version
      */
     public ChannelChange(Channel oldChannel, Channel newChannel, Status status) {
         this.status = status;
@@ -80,7 +80,7 @@ public Optional<Channel> getNewChannel() {
     /**
      * name of the modified channel
      *
-     * @return
+     * @return - name of the channel
      */
     public String getName() {
         return newChannel.isPresent() ? newChannel.get().getName() : oldChannel.get().getName();

src/main/java/org/wildfly/installationmanager/ManifestVersion.java

@@ -25,7 +25,7 @@
 public class ManifestVersion {
 
     /**
-     * Type of the channel manifest - Maven GAV or an URL
+     * Type of the channel manifest - Maven GAV or a URL
      */
     public enum Type {MAVEN, URL}
 
@@ -47,23 +47,23 @@ public ManifestVersion(String channelId, String description, String version, Typ
 
     /**
      * channel identifier - either Maven coordinate or an URL
-     * @return
+     * @return channel identifier
      */
     public String getChannelId() {
         return channelId;
     }
 
     /**
      * human read-able description of the channel version. Can be null if the description is not available.
-     * @return
+     * @return channel description
      */
     public String getDescription() {
         return description;
     }
 
     /**
      * version of the channel manifest. If the manifest is provided by URL, the hash of the resolved manifest is used instead of version
-     * @return
+     * @return channel version
      */
     public String getVersion() {
         return version;

src/main/java/org/wildfly/installationmanager/spi/InstallationManagerFactory.java

@@ -27,15 +27,16 @@ public interface InstallationManagerFactory {
      * Creates InstallationManger for server instance located at {@code installationDir}.
      * If the provided directory is empty, the manger needs to install the server before attempting any other operations.
      *
-     * @param installationDir
-     * @param mavenOptions
-     * @return
+     * @param installationDir the directory where the server is installed
+     * @param mavenOptions    the options to be used by the manager
+     * @return the InstallationManager instance
      */
     InstallationManager create(Path installationDir, MavenOptions mavenOptions) throws Exception;
 
     /**
      * Gets the name of InstallationManager instance
-     * @return
+     *
+     * @return the name of the InstallationManger
      */
     String getName();
 }