[MINOR] Fix JDocs

exclude protobuf in Jdocs

Closes #923
diff --git a/pom.xml b/pom.xml
index 54cfb85..0f4e208 100644
--- a/pom.xml
+++ b/pom.xml
@@ -671,6 +671,9 @@
 						<groupId>org.apache.maven.plugins</groupId>
 						<artifactId>maven-javadoc-plugin</artifactId>
 						<version>3.1.1</version>
+						<configuration>
+							<excludePackageNames>org.apache.systeds.protobuf.*</excludePackageNames>
+						</configuration>
 						<executions>
 							<execution>
 								<id>attach-javadocs</id>
diff --git a/src/main/java/org/apache/sysds/runtime/matrix/data/FrameBlock.java b/src/main/java/org/apache/sysds/runtime/matrix/data/FrameBlock.java
index a27511a..5cbd3de 100644
--- a/src/main/java/org/apache/sysds/runtime/matrix/data/FrameBlock.java
+++ b/src/main/java/org/apache/sysds/runtime/matrix/data/FrameBlock.java
@@ -1875,7 +1875,7 @@
 	 *  if data value in any cell is greater than the specified threshold of that attribute
 	 *  the output frame will store a null on that cell position, thus removing the length-violating values.
 	 * 
-	 *  @param row vector of valid lengths
+	 *  @param feaLen vector of valid lengths
 	 *  @return FrameBlock with invalid values converted into missing values (null)
 	 */
 	public FrameBlock invalidByLength(MatrixBlock feaLen) {