diff --git a/.gitignore b/.gitignore
index 4a4272142..45bb7f5d1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,7 +7,7 @@ target/
 .ipynb_checkpoints/
 *.iml
 /bin/
-*.jar
+rumble*.jar
 *.*~
 
 # for now ignore jsound package
diff --git a/README.md b/README.md
index 7e4866c15..d82971f2b 100644
--- a/README.md
+++ b/README.md
@@ -16,4 +16,4 @@ The documentation also contains an introduction specific to RumbleDB and how you
 
 [The documentation of the current master (for the adventurous and curious) is available here.](http://sparksoniq.readthedocs.io/en/latest/)
 
-RumbleDB is an effort involving many researchers and ETH Zurich students: code and support by Stefan Irimescu, Ghislain Fourny, Gustavo Alonso, Renato Marroquin, Rodrigo Bruno, Falko Noé, Ioana Stefan, Andrea Rinaldi, Stevan Mihajlovic, Mario Arduini, Can Berker Çıkış, Elwin Stephan, David Dao, Zirun Wang, Ingo Müller, Dan-Ovidiu Graur, Thomas Zhou, Olivier Goerens, Alexandru Meterez, Remo Röthlisberger, Dominik Bruggisser, David Loughlin, David Buzatu.
+RumbleDB is an effort involving many researchers and ETH Zurich students: code and support by Stefan Irimescu, Ghislain Fourny, Gustavo Alonso, Renato Marroquin, Rodrigo Bruno, Falko Noé, Ioana Stefan, Andrea Rinaldi, Stevan Mihajlovic, Mario Arduini, Can Berker Çıkış, Elwin Stephan, David Dao, Zirun Wang, Ingo Müller, Dan-Ovidiu Graur, Thomas Zhou, Olivier Goerens, Alexandru Meterez, Remo Röthlisberger, Dominik Bruggisser, David Loughlin, David Buzatu, Marco Schöb.
diff --git a/docs/install.md b/docs/install.md
index 98f158a46..6141f7c47 100644
--- a/docs/install.md
+++ b/docs/install.md
@@ -7,8 +7,8 @@ We show here how to install RumbleDB from the github repository if you wish to d
 The following software is required:
 
 - [Java SE](http://www.oracle.com/technetwork/java/javase/downloads/index.html) 8 (last tested on OpenJDK 8u251). The version of Java is important, as Spark only works with Java 8 or java 11.
-- [Spark](https://spark.apache.org/), version 3.4.3 (for example)
-- [Ant](http://www.ant.org/), version 1.11.1
+- [Spark](https://spark.apache.org/), version 3.4.4 (for example)
+- [Ant](https://ant.apache.org/), version 1.11.1
 - [ANTLR](http://www.ant.org/), version 4.9.3 (supplied in our repository)
 - [Maven](https://maven.apache.org/) 3.6.0
 
diff --git a/pom.xml b/pom.xml
index 43b5e3fec..66cd01ed1 100644
--- a/pom.xml
+++ b/pom.xml
@@ -46,9 +46,10 @@
                     <compilerId>eclipse</compilerId>
                     <source>1.8</source>
                     <target>1.8</target>
-                    <compilerArguments>
-                        <properties>${project.basedir}/org.eclipse.jdt.core.prefs</properties>
-                    </compilerArguments>
+                    <compilerArgs>
+                        <arg>-properties</arg>
+                        <arg>${project.basedir}/org.eclipse.jdt.core.prefs</arg>
+                    </compilerArgs>
                 </configuration>
                 <dependencies>
                     <dependency>
@@ -63,6 +64,14 @@
                     </dependency>
                 </dependencies>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-resources-plugin</artifactId>
+                <version>3.3.1</version>
+                <configuration>
+                    <encoding>UTF-8</encoding>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-jar-plugin</artifactId>
@@ -150,6 +159,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-release-plugin</artifactId>
+                <version>3.0.1</version>
                 <configuration>
                     <localCheckout>true</localCheckout>
                     <pushChanges>false</pushChanges>
diff --git a/src/main/java/org/rumbledb/compiler/ExecutionModeVisitor.java b/src/main/java/org/rumbledb/compiler/ExecutionModeVisitor.java
index e96188dbc..db847abd4 100644
--- a/src/main/java/org/rumbledb/compiler/ExecutionModeVisitor.java
+++ b/src/main/java/org/rumbledb/compiler/ExecutionModeVisitor.java
@@ -657,7 +657,7 @@ public StaticContext visitProlog(Prolog prolog, StaticContext argument) {
     public StaticContext visitProgram(Program program, StaticContext argument) {
         visitDescendants(program, argument);
         ExecutionMode mergedExecutionMode = program.getStatementsAndOptionalExpr().getHighestExecutionMode();
-        for (Statement statement : exitStatementChildren) {
+        for (Statement statement : this.exitStatementChildren) {
             ExecutionMode statementExecMode = statement.getHighestExecutionMode(this.visitorConfig);
             mergedExecutionMode = getHighestExecutionMode(mergedExecutionMode, statementExecMode);
         }
diff --git a/src/main/java/org/rumbledb/compiler/SequentialClassificationVisitor.java b/src/main/java/org/rumbledb/compiler/SequentialClassificationVisitor.java
index 812239241..72a47fa8b 100644
--- a/src/main/java/org/rumbledb/compiler/SequentialClassificationVisitor.java
+++ b/src/main/java/org/rumbledb/compiler/SequentialClassificationVisitor.java
@@ -57,7 +57,7 @@ public class SequentialClassificationVisitor extends AbstractNodeVisitor<Descend
     public SequentialClassificationVisitor(Prolog prolog) {
         this.prolog = prolog;
         this.blockLevel = 0;
-        variableBlockLevel = new HashMap<>();
+        this.variableBlockLevel = new HashMap<>();
     }
 
     protected DescendentSequentialProperties defaultAction(Node node, DescendentSequentialProperties argument) {
diff --git a/src/main/java/org/rumbledb/context/GlobalVariables.java b/src/main/java/org/rumbledb/context/GlobalVariables.java
index ce93dec24..18754fb13 100644
--- a/src/main/java/org/rumbledb/context/GlobalVariables.java
+++ b/src/main/java/org/rumbledb/context/GlobalVariables.java
@@ -15,7 +15,7 @@ public class GlobalVariables implements Serializable, KryoSerializable {
     private Set<Name> globalVariables;
 
     public GlobalVariables() {
-        globalVariables = new HashSet<>();
+        this.globalVariables = new HashSet<>();
     }
 
     public void addGlobalVariable(Name globalVariable) {
diff --git a/src/main/java/org/rumbledb/context/InScopeVariable.java b/src/main/java/org/rumbledb/context/InScopeVariable.java
index 31510fc20..5edbf536f 100644
--- a/src/main/java/org/rumbledb/context/InScopeVariable.java
+++ b/src/main/java/org/rumbledb/context/InScopeVariable.java
@@ -83,6 +83,6 @@ public void read(Kryo kryo, Input input) {
     }
 
     public boolean isAssignable() {
-        return isAssignable;
+        return this.isAssignable;
     }
 }
diff --git a/src/main/java/org/rumbledb/expressions/module/VariableDeclaration.java b/src/main/java/org/rumbledb/expressions/module/VariableDeclaration.java
index 66b973b2a..e7c1f64f0 100644
--- a/src/main/java/org/rumbledb/expressions/module/VariableDeclaration.java
+++ b/src/main/java/org/rumbledb/expressions/module/VariableDeclaration.java
@@ -166,12 +166,12 @@ public void serializeToJSONiq(StringBuffer sb, int indent) {
 
     @Nullable
     public List<Annotation> getAnnotations() {
-        return annotations;
+        return this.annotations;
     }
 
 
     public boolean isAssignable() {
-        return isAssignable;
+        return this.isAssignable;
     }
 }
 
diff --git a/src/main/java/org/rumbledb/expressions/primary/InlineFunctionExpression.java b/src/main/java/org/rumbledb/expressions/primary/InlineFunctionExpression.java
index 95f05b526..399082c07 100644
--- a/src/main/java/org/rumbledb/expressions/primary/InlineFunctionExpression.java
+++ b/src/main/java/org/rumbledb/expressions/primary/InlineFunctionExpression.java
@@ -138,7 +138,7 @@ public StatementsAndOptionalExpr getBody() {
 
     @Nullable
     public List<Annotation> getAnnotations() {
-        return annotations;
+        return this.annotations;
     }
 
     @Override
@@ -252,7 +252,7 @@ public void serializeToJSONiq(StringBuffer sb, int indent) {
     }
 
     public boolean hasSequentialPropertyAnnotation() {
-        return hasSequentialPropertyAnnotation;
+        return this.hasSequentialPropertyAnnotation;
     }
 
     public void setHasExitStatement(boolean hasExitStatement) {
diff --git a/src/main/java/org/rumbledb/expressions/scripting/annotations/Annotation.java b/src/main/java/org/rumbledb/expressions/scripting/annotations/Annotation.java
index 888a0a073..d56dbf09e 100644
--- a/src/main/java/org/rumbledb/expressions/scripting/annotations/Annotation.java
+++ b/src/main/java/org/rumbledb/expressions/scripting/annotations/Annotation.java
@@ -20,11 +20,11 @@ public Annotation(Name annotationName, List<Expression> literals) {
     }
 
     public Name getAnnotationName() {
-        return annotationName;
+        return this.annotationName;
     }
 
     public List<Expression> getLiterals() {
-        return literals;
+        return this.literals;
     }
 
     public static boolean checkAssignable(
diff --git a/src/main/java/org/rumbledb/expressions/scripting/block/BlockStatement.java b/src/main/java/org/rumbledb/expressions/scripting/block/BlockStatement.java
index 075209262..281bc1989 100644
--- a/src/main/java/org/rumbledb/expressions/scripting/block/BlockStatement.java
+++ b/src/main/java/org/rumbledb/expressions/scripting/block/BlockStatement.java
@@ -27,7 +27,7 @@ public <T> T accept(AbstractNodeVisitor<T> visitor, T argument) {
     @Override
     public List<Node> getChildren() {
         List<Node> result = new ArrayList<>();
-        blockStatements.forEach(statement -> {
+        this.blockStatements.forEach(statement -> {
             if (statement != null) {
                 result.add(statement);
             }
@@ -49,6 +49,6 @@ public void serializeToJSONiq(StringBuffer sb, int indent) {
     }
 
     public List<Statement> getBlockStatements() {
-        return blockStatements;
+        return this.blockStatements;
     }
 }
diff --git a/src/main/java/org/rumbledb/expressions/scripting/control/SwitchStatement.java b/src/main/java/org/rumbledb/expressions/scripting/control/SwitchStatement.java
index a19182d91..f6bc43efc 100644
--- a/src/main/java/org/rumbledb/expressions/scripting/control/SwitchStatement.java
+++ b/src/main/java/org/rumbledb/expressions/scripting/control/SwitchStatement.java
@@ -74,14 +74,14 @@ public void serializeToJSONiq(StringBuffer sb, int indent) {
     }
 
     public Expression getTestCondition() {
-        return testCondition;
+        return this.testCondition;
     }
 
     public List<SwitchCaseStatement> getCases() {
-        return cases;
+        return this.cases;
     }
 
     public Statement getDefaultStatement() {
-        return defaultStatement;
+        return this.defaultStatement;
     }
 }
diff --git a/src/main/java/org/rumbledb/expressions/scripting/declaration/CommaVariableDeclStatement.java b/src/main/java/org/rumbledb/expressions/scripting/declaration/CommaVariableDeclStatement.java
index b39f605b6..5eb42d9bc 100644
--- a/src/main/java/org/rumbledb/expressions/scripting/declaration/CommaVariableDeclStatement.java
+++ b/src/main/java/org/rumbledb/expressions/scripting/declaration/CommaVariableDeclStatement.java
@@ -23,18 +23,18 @@ public <T> T accept(AbstractNodeVisitor<T> visitor, T argument) {
 
     @Override
     public List<Node> getChildren() {
-        return new ArrayList<>(variables);
+        return new ArrayList<>(this.variables);
     }
 
     @Override
     public void serializeToJSONiq(StringBuffer sb, int indent) {
         indentIt(sb, indent);
-        for (VariableDeclStatement variableDeclStatement : variables) {
+        for (VariableDeclStatement variableDeclStatement : this.variables) {
             variableDeclStatement.serializeToJSONiq(sb, 0);
         }
     }
 
     public List<VariableDeclStatement> getVariables() {
-        return variables;
+        return this.variables;
     }
 }
diff --git a/src/main/java/org/rumbledb/expressions/scripting/declaration/VariableDeclStatement.java b/src/main/java/org/rumbledb/expressions/scripting/declaration/VariableDeclStatement.java
index 5f3d3fb7e..7aa12568d 100644
--- a/src/main/java/org/rumbledb/expressions/scripting/declaration/VariableDeclStatement.java
+++ b/src/main/java/org/rumbledb/expressions/scripting/declaration/VariableDeclStatement.java
@@ -103,10 +103,10 @@ public Expression getVariableExpression() {
     }
 
     public List<Annotation> getAnnotations() {
-        return annotations;
+        return this.annotations;
     }
 
     public boolean isAssignable() {
-        return isAssignable;
+        return this.isAssignable;
     }
 }
diff --git a/src/main/java/org/rumbledb/expressions/scripting/loops/ExitStatement.java b/src/main/java/org/rumbledb/expressions/scripting/loops/ExitStatement.java
index abe9f8a28..eec89443d 100644
--- a/src/main/java/org/rumbledb/expressions/scripting/loops/ExitStatement.java
+++ b/src/main/java/org/rumbledb/expressions/scripting/loops/ExitStatement.java
@@ -34,7 +34,7 @@ public void serializeToJSONiq(StringBuffer sb, int indent) {
     }
 
     public Expression getExitExpression() {
-        return exitExpression;
+        return this.exitExpression;
     }
 
 }
diff --git a/src/main/java/org/rumbledb/expressions/scripting/loops/FlowrStatement.java b/src/main/java/org/rumbledb/expressions/scripting/loops/FlowrStatement.java
index ab9c208e8..1954f52fa 100644
--- a/src/main/java/org/rumbledb/expressions/scripting/loops/FlowrStatement.java
+++ b/src/main/java/org/rumbledb/expressions/scripting/loops/FlowrStatement.java
@@ -48,6 +48,6 @@ public void serializeToJSONiq(StringBuffer sb, int indent) {
     }
 
     public ReturnStatementClause getReturnStatementClause() {
-        return returnStatementClause;
+        return this.returnStatementClause;
     }
 }
diff --git a/src/main/java/org/rumbledb/expressions/scripting/loops/ReturnStatementClause.java b/src/main/java/org/rumbledb/expressions/scripting/loops/ReturnStatementClause.java
index 6eb09f720..49c67fe7e 100644
--- a/src/main/java/org/rumbledb/expressions/scripting/loops/ReturnStatementClause.java
+++ b/src/main/java/org/rumbledb/expressions/scripting/loops/ReturnStatementClause.java
@@ -46,6 +46,6 @@ public void serializeToJSONiq(StringBuffer sb, int indent) {
     }
 
     public Statement getReturnStatement() {
-        return returnStatement;
+        return this.returnStatement;
     }
 }
diff --git a/src/main/java/org/rumbledb/expressions/scripting/loops/WhileStatement.java b/src/main/java/org/rumbledb/expressions/scripting/loops/WhileStatement.java
index dfbe3bc2a..72172b06b 100644
--- a/src/main/java/org/rumbledb/expressions/scripting/loops/WhileStatement.java
+++ b/src/main/java/org/rumbledb/expressions/scripting/loops/WhileStatement.java
@@ -27,8 +27,8 @@ public <T> T accept(AbstractNodeVisitor<T> visitor, T argument) {
     @Override
     public List<Node> getChildren() {
         List<Node> result = new ArrayList<>();
-        result.add(testCondition);
-        result.add(statement);
+        result.add(this.testCondition);
+        result.add(this.statement);
         return result;
     }
 
@@ -43,10 +43,10 @@ public void serializeToJSONiq(StringBuffer sb, int indent) {
     }
 
     public Expression getTestCondition() {
-        return testCondition;
+        return this.testCondition;
     }
 
     public Statement getStatement() {
-        return statement;
+        return this.statement;
     }
 }
diff --git a/src/main/java/org/rumbledb/runtime/functions/StaticUserDefinedFunctionCallIterator.java b/src/main/java/org/rumbledb/runtime/functions/StaticUserDefinedFunctionCallIterator.java
index 326e01ae7..c3e7af696 100644
--- a/src/main/java/org/rumbledb/runtime/functions/StaticUserDefinedFunctionCallIterator.java
+++ b/src/main/java/org/rumbledb/runtime/functions/StaticUserDefinedFunctionCallIterator.java
@@ -131,7 +131,7 @@ protected void closeLocal() {
 
     public void setNextResult() {
         this.nextResult = null;
-        if (!encounteredExitStatement) {
+        if (!this.encounteredExitStatement) {
             try {
                 if (this.userDefinedFunctionCallIterator.hasNext()) {
                     this.nextResult = this.userDefinedFunctionCallIterator.next();
diff --git a/src/main/java/org/rumbledb/runtime/scripting/ProgramIterator.java b/src/main/java/org/rumbledb/runtime/scripting/ProgramIterator.java
index 91970ed72..0d7201275 100644
--- a/src/main/java/org/rumbledb/runtime/scripting/ProgramIterator.java
+++ b/src/main/java/org/rumbledb/runtime/scripting/ProgramIterator.java
@@ -89,7 +89,7 @@ private void setPULFromExitStatement(ExitStatementException exitStatementExcepti
 
     @Override
     protected Item nextLocal() {
-        if (!encounteredExitStatement) {
+        if (!this.encounteredExitStatement) {
             try {
                 return this.statementsAndExprIterator.next();
             } catch (ExitStatementException exitStatementException) {
@@ -117,7 +117,7 @@ public boolean isUpdating() {
 
     @Override
     public PendingUpdateList getPendingUpdateList(DynamicContext context) {
-        if (!encounteredExitStatement) {
+        if (!this.encounteredExitStatement) {
             return this.statementsAndExprIterator.getPendingUpdateList(context);
         }
         return this.pendingUpdateList;
diff --git a/src/main/java/org/rumbledb/runtime/scripting/block/StatementsWithExprIterator.java b/src/main/java/org/rumbledb/runtime/scripting/block/StatementsWithExprIterator.java
index bf035392d..a80021b76 100644
--- a/src/main/java/org/rumbledb/runtime/scripting/block/StatementsWithExprIterator.java
+++ b/src/main/java/org/rumbledb/runtime/scripting/block/StatementsWithExprIterator.java
@@ -32,7 +32,7 @@ public StatementsWithExprIterator(
         this.children.addAll(statements);
         this.children.add(exprIterator);
 
-        for (RuntimeIterator child : children) {
+        for (RuntimeIterator child : this.children) {
             if (child.isSequential()) {
                 this.isSequential = child.isSequential();
             }
diff --git a/src/main/java/org/rumbledb/runtime/scripting/loops/ExitStatementIterator.java b/src/main/java/org/rumbledb/runtime/scripting/loops/ExitStatementIterator.java
index ca07d7336..5500dedea 100644
--- a/src/main/java/org/rumbledb/runtime/scripting/loops/ExitStatementIterator.java
+++ b/src/main/java/org/rumbledb/runtime/scripting/loops/ExitStatementIterator.java
@@ -72,7 +72,9 @@ protected Item nextLocal() {
         this.result = this.childIterator.materialize(this.currentDynamicContextForLocalExecution);
         this.pendingUpdateList = new PendingUpdateList();
         if (this.childIterator.isUpdating()) {
-            pendingUpdateList = this.childIterator.getPendingUpdateList(this.currentDynamicContextForLocalExecution);
+            this.pendingUpdateList = this.childIterator.getPendingUpdateList(
+                this.currentDynamicContextForLocalExecution
+            );
         }
         throw new ExitStatementException(
                 this.pendingUpdateList,
diff --git a/src/main/java/org/rumbledb/runtime/typing/TreatIterator.java b/src/main/java/org/rumbledb/runtime/typing/TreatIterator.java
index 39f972fe1..f3b9d643e 100644
--- a/src/main/java/org/rumbledb/runtime/typing/TreatIterator.java
+++ b/src/main/java/org/rumbledb/runtime/typing/TreatIterator.java
@@ -240,7 +240,7 @@ public JSoundDataFrame getDataFrame(DynamicContext dynamicContext) {
 
     @Override
     public PendingUpdateList getPendingUpdateList(DynamicContext context) {
-        return iterator.getPendingUpdateList(context);
+        return this.iterator.getPendingUpdateList(context);
     }
 
     /**