diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index 617367bf42..fb8f53cf3a 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -10,6 +10,7 @@ on:
   pull_request:
     branches:
       - '**'
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/pom.xml b/pom.xml
index 8a0e899018..b55b471d32 100644
--- a/pom.xml
+++ b/pom.xml
@@ -61,7 +61,7 @@
                     <dependency>
                         <groupId>org.eclipse.jdt</groupId>
                         <artifactId>ecj</artifactId>
-                        <version>3.43.0</version>
+                       <version>3.43.0</version>
                     </dependency>
                 </dependencies>
             </plugin>
@@ -278,25 +278,25 @@
         <dependency>
             <groupId>org.apache.spark</groupId>
             <artifactId>spark-core_2.13</artifactId>
-            <version>4.0.1</version>
+            <version>4.1.1</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>org.apache.spark</groupId>
             <artifactId>spark-sql_2.13</artifactId>
-            <version>4.0.1</version>
+            <version>4.1.1</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>org.apache.spark</groupId>
             <artifactId>spark-mllib_2.13</artifactId>
-            <version>4.0.1</version>
+            <version>4.1.1</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>org.apache.spark</groupId>
             <artifactId>spark-hive_2.13</artifactId>
-            <version>4.0.1</version>
+            <version>4.1.1</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
@@ -308,7 +308,7 @@
         <dependency>
             <groupId>org.apache.spark</groupId>
             <artifactId>spark-avro_2.13</artifactId>
-            <version>4.0.1</version>
+            <version>4.1.1</version>
         </dependency>
         <dependency>
             <groupId>org.antlr</groupId>
@@ -375,7 +375,7 @@
         <dependency>
             <groupId>io.delta</groupId>
             <artifactId>delta-spark_2.13</artifactId>
-            <version>4.0.0</version>
+            <version>4.1.0</version>
         </dependency>
         <dependency>
             <groupId>org.apache.iceberg</groupId>
@@ -405,6 +405,12 @@
             <artifactId>mongo-spark-connector_2.13</artifactId>
             <version>10.5.0</version>
         </dependency>
+        <dependency>
+            <groupId>org.apache.logging.log4j</groupId>
+            <artifactId>log4j-core</artifactId>
+            <version>2.24.3</version>
+            <scope>compile</scope>
+        </dependency>
     </dependencies>
 
     <distributionManagement>
diff --git a/src/main/java/org/rumbledb/types/DerivedAtomicItemType.java b/src/main/java/org/rumbledb/types/DerivedAtomicItemType.java
index 1053baab87..8af620d449 100644
--- a/src/main/java/org/rumbledb/types/DerivedAtomicItemType.java
+++ b/src/main/java/org/rumbledb/types/DerivedAtomicItemType.java
@@ -1,6 +1,9 @@
 package org.rumbledb.types;
 
-import org.apache.commons.collections.ListUtils;
+import java.util.List;
+import java.util.Set;
+
+import org.apache.commons.collections4.ListUtils;
 import org.rumbledb.api.Item;
 import org.rumbledb.config.RumbleRuntimeConfiguration;
 import org.rumbledb.context.DynamicContext;
@@ -11,9 +14,6 @@
 import org.rumbledb.expressions.comparison.ComparisonExpression;
 import org.rumbledb.runtime.misc.ComparisonIterator;
 
-import java.util.List;
-import java.util.Set;
-
 public class DerivedAtomicItemType implements ItemType {
 
     private static final long serialVersionUID = 1L;
diff --git a/src/main/java/org/rumbledb/types/ObjectItemType.java b/src/main/java/org/rumbledb/types/ObjectItemType.java
index 5fa5c4e7f0..94abecaa0e 100644
--- a/src/main/java/org/rumbledb/types/ObjectItemType.java
+++ b/src/main/java/org/rumbledb/types/ObjectItemType.java
@@ -1,6 +1,16 @@
 package org.rumbledb.types;
 
-import org.apache.commons.collections.ListUtils;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.commons.collections4.ListUtils;
 import org.rumbledb.api.Item;
 import org.rumbledb.config.RumbleRuntimeConfiguration;
 import org.rumbledb.context.DynamicContext;
@@ -10,8 +20,6 @@
 import org.rumbledb.exceptions.InvalidSchemaException;
 import org.rumbledb.exceptions.OurBadException;
 
-import java.util.*;
-
 public class ObjectItemType implements ItemType {
 
     private static final long serialVersionUID = 1L;
diff --git a/src/test/resources/test_files/RumbleML/RumbleML/EstimatorTests/MLEstimator-MinMaxScaler.jq b/src/test/resources/test_files/RumbleML/RumbleML/EstimatorTests/MLEstimator-MinMaxScaler.jq
index 656f36baaa..23bce27154 100644
--- a/src/test/resources/test_files/RumbleML/RumbleML/EstimatorTests/MLEstimator-MinMaxScaler.jq
+++ b/src/test/resources/test_files/RumbleML/RumbleML/EstimatorTests/MLEstimator-MinMaxScaler.jq
@@ -1,4 +1,4 @@
-(:JIQS: ShouldRun; Output="({ "label" : 0, "name" : "a", "age" : 20, "weight" : 50, "scaled" : { } }, { "label" : 1, "name" : "b", "age" : 21, "weight" : 55.3, "scaled" : [ 0.2, 0.20703124999999992 ] }, { "label" : 2, "name" : "c", "age" : 22, "weight" : 60.6, "scaled" : [ 0.4, 0.4140625000000001 ] }, { "label" : 3, "name" : "d", "age" : 23, "weight" : 65.9, "scaled" : [ 0.6000000000000001, 0.6210937500000003 ] }, { "label" : 4, "name" : "e", "age" : 24, "weight" : 70.3, "scaled" : [ 0.8, 0.79296875 ] }, { "label" : 5, "name" : "f", "age" : 25, "weight" : 75.6, "scaled" : [ 1, 1 ] })" :)
+(:JIQS: ShouldRun; Output="({ "label" : 0, "name" : "a", "age" : 20, "weight" : 50, "scaled" : [ 0, 0 ] }, { "label" : 1, "name" : "b", "age" : 21, "weight" : 55.3, "scaled" : [ 0.2, 0.20703124999999992 ] }, { "label" : 2, "name" : "c", "age" : 22, "weight" : 60.6, "scaled" : [ 0.4, 0.4140625000000001 ] }, { "label" : 3, "name" : "d", "age" : 23, "weight" : 65.9, "scaled" : [ 0.6000000000000001, 0.6210937500000003 ] }, { "label" : 4, "name" : "e", "age" : 24, "weight" : 70.3, "scaled" : [ 0.8, 0.79296875 ] }, { "label" : 5, "name" : "f", "age" : 25, "weight" : 75.6, "scaled" : [ 1, 1 ] })" :)
 let $data := annotate(
     json-lines("../../../../queries/rumbleML/sample-ml-data-flat.json"),
     { "label": "integer", "binaryLabel": "integer", "name": "string", "age": "double", "weight": "double", "booleanCol": "boolean", "nullCol": "null", "stringCol": "string", "stringArrayCol": ["string"], "intArrayCol": ["integer"],  "doubleArrayCol": ["double"],  "doubleArrayArrayCol": [["double"]] }
diff --git a/src/test/resources/test_files/RumbleML/RumbleML/EstimatorTests/MLEstimator-PCA.jq b/src/test/resources/test_files/RumbleML/RumbleML/EstimatorTests/MLEstimator-PCA.jq
index 212d57db83..692ec61697 100644
--- a/src/test/resources/test_files/RumbleML/RumbleML/EstimatorTests/MLEstimator-PCA.jq
+++ b/src/test/resources/test_files/RumbleML/RumbleML/EstimatorTests/MLEstimator-PCA.jq
@@ -1,4 +1,4 @@
-(:JIQS: ShouldRun; Output="({ "label" : 0, "name" : "a", "age" : 20, "weight" : 50, "pca" : { } }, { "label" : 1, "name" : "b", "age" : 21, "weight" : 55.3, "pca" : [ 0.2, 0.20703124999999992 ] }, { "label" : 2, "name" : "c", "age" : 22, "weight" : 60.6, "pca" : [ 0.4, 0.4140625000000001 ] }, { "label" : 3, "name" : "d", "age" : 23, "weight" : 65.9, "pca" : [ 0.6000000000000001, 0.6210937500000003 ] }, { "label" : 4, "name" : "e", "age" : 24, "weight" : 70.3, "pca" : [ 0.8, 0.79296875 ] }, { "label" : 5, "name" : "f", "age" : 25, "weight" : 75.6, "pca" : [ 1, 1 ] })" :)
+(:JIQS: ShouldRun; Output="({ "label" : 0, "name" : "a", "age" : 20, "weight" : 50, "pca" : [ 0, 0 ] }, { "label" : 1, "name" : "b", "age" : 21, "weight" : 55.3, "pca" : [ 0.2, 0.20703124999999992 ] }, { "label" : 2, "name" : "c", "age" : 22, "weight" : 60.6, "pca" : [ 0.4, 0.4140625000000001 ] }, { "label" : 3, "name" : "d", "age" : 23, "weight" : 65.9, "pca" : [ 0.6000000000000001, 0.6210937500000003 ] }, { "label" : 4, "name" : "e", "age" : 24, "weight" : 70.3, "pca" : [ 0.8, 0.79296875 ] }, { "label" : 5, "name" : "f", "age" : 25, "weight" : 75.6, "pca" : [ 1, 1 ] })" :)
 let $data := annotate(
     json-lines("../../../../queries/rumbleML/sample-ml-data-flat.json"),
     { "label": "integer", "binaryLabel": "integer", "name": "string", "age": "double", "weight": "double", "booleanCol": "boolean", "nullCol": "null", "stringCol": "string", "stringArrayCol": ["string"], "intArrayCol": ["integer"],  "doubleArrayCol": ["double"],  "doubleArrayArrayCol": [["double"]] }