DRILL-6389: Fixed building javadocs

 - Added documentation about how to build javadocs
 - Fixed some of the javadoc warnings

closes #1276

2 files changed, 5 insertions, 8 deletions

diff --git a/exec/java-exec/src/main/java/org/apache/drill/exec/util/ImpersonationUtil.java b/exec/java-exec/src/main/java/org/apache/drill/exec/util/ImpersonationUtil.java
index b74ce1aee..c9039e9b0 100644
--- a/exec/java-exec/src/main/java/org/apache/drill/exec/util/ImpersonationUtil.java
+++ b/exec/java-exec/src/main/java/org/apache/drill/exec/util/ImpersonationUtil.java
@@ -110,7 +110,6 @@ public class ImpersonationUtil {
    * @param opUserName Name of the user whom to impersonate while setting up the operator.
    * @param queryUserName Name of the user who issues the query. If <i>opUserName</i> is invalid,
    *                      then this parameter must be valid user name.
-   * @return
    */
   public static UserGroupInformation createProxyUgi(String opUserName, String queryUserName) {
     if (!Strings.isNullOrEmpty(opUserName)) {
@@ -131,7 +130,6 @@ public class ImpersonationUtil {
    * Create and return proxy user {@link org.apache.hadoop.security.UserGroupInformation} for give user name.
    *
    * @param proxyUserName Proxy user name (must be valid)
-   * @return
    */
   public static UserGroupInformation createProxyUgi(String proxyUserName) {
     try {
@@ -202,7 +200,6 @@ public class ImpersonationUtil {
    *
    * @param proxyUserName Name of the user whom to impersonate while accessing the FileSystem contents.
    * @param fsConf FileSystem configuration.
-   * @return
    */
   public static DrillFileSystem createFileSystem(String proxyUserName, Configuration fsConf) {
     return createFileSystem(createProxyUgi(proxyUserName), fsConf, null);
@@ -234,7 +231,7 @@ public class ImpersonationUtil {
    * @param userName User who is checked for administrative privileges.
    * @param adminUsers Comma separated list of admin usernames,
    * @param adminGroups Comma separated list of admin usergroups
-   * @return
+   * @return True if the user has admin priveleges. False otherwise.
    */
   public static boolean hasAdminPrivileges(final String userName, final String adminUsers, final String adminGroups) {
     // Process user is by default an admin
diff --git a/exec/java-exec/src/main/java/org/apache/drill/exec/util/Utilities.java b/exec/java-exec/src/main/java/org/apache/drill/exec/util/Utilities.java
index a165d9e32..f8fb8d77a 100644
--- a/exec/java-exec/src/main/java/org/apache/drill/exec/util/Utilities.java
+++ b/exec/java-exec/src/main/java/org/apache/drill/exec/util/Utilities.java
@@ -56,11 +56,11 @@ public class Utilities {
   }
 
   /**
-   * Create QueryContextInformation with given <i>defaultSchemaName</i>. Rest of the members of the
+   * Create {@link org.apache.drill.exec.proto.BitControl.QueryContextInformation} with given <i>defaultSchemaName</i>. Rest of the members of the
    * QueryContextInformation is derived from the current state of the process.
    *
    * @param defaultSchemaName
-   * @return
+   * @return A {@link org.apache.drill.exec.proto.BitControl.QueryContextInformation} with given <i>defaultSchemaName</i>.
    */
   public static QueryContextInformation createQueryContextInfo(final String defaultSchemaName, final String sessionId) {
     final long queryStartTime = System.currentTimeMillis();
@@ -75,7 +75,7 @@ public class Utilities {
 
   /**
    * Read the manifest file and get the Drill version number
-   * @return
+   * @return The Drill version.
    */
   public static String getDrillVersion() {
       String v = Utilities.class.getPackage().getImplementationVersion();
@@ -85,7 +85,7 @@ public class Utilities {
   /**
    * Return true if list of schema path has star column.
    * @param projected
-   * @return
+   * @return True if the list of {@link org.apache.drill.common.expression.SchemaPath}s has star column.
    */
   public static boolean isStarQuery(Collection<SchemaPath> projected) {
     return Iterables.tryFind(Preconditions.checkNotNull(projected, COL_NULL_ERROR), new Predicate<SchemaPath>() {