diff --git a/src/main/java/com/erikmafo/btviewer/services/query/QueryResultConverter.java b/src/main/java/com/erikmafo/btviewer/services/query/QueryResultConverter.java
index be46e1a..1fbd22b 100644
--- a/src/main/java/com/erikmafo/btviewer/services/query/QueryResultConverter.java
+++ b/src/main/java/com/erikmafo/btviewer/services/query/QueryResultConverter.java
@@ -138,17 +138,25 @@ private Aggregation createAggregationEntry(AggregationExpression aggregationExpr
     }
 
     private double getDouble(BigtableCell cell) {
-        if (valueConverter.isNumberCellDefinition(cell)) {
-            return ((Number)valueConverter.convert(cell)).doubleValue();
-        } else {
-            return 0;
-        }
+        return valueConverter.isNumberCellDefinition(cell) ? ((Number)valueConverter.convert(cell)).doubleValue() : 0;
     }
 
     private boolean matches(@NotNull Field field, @NotNull RowCell cell) {
-        return field.isAsterisk() || (field.hasQualifier()
-                && cell.getFamily().equalsIgnoreCase(field.getFamily())
-                && cell.getQualifier().toStringUtf8().equalsIgnoreCase(field.getQualifier()));
+        if (field.isAsterisk()) {
+            return true;
+        }
+
+        return field.hasQualifier()
+                ? matchesFamily(field, cell) && matchesQualifier(field, cell)
+                : matchesFamily(field, cell);
+    }
+
+    private boolean matchesFamily(@NotNull Field field, @NotNull RowCell cell) {
+        return cell.getFamily().equalsIgnoreCase(field.getFamily());
+    }
+
+    private boolean matchesQualifier(@NotNull Field field, @NotNull RowCell cell) {
+        return cell.getQualifier().toStringUtf8().equalsIgnoreCase(field.getQualifier());
     }
 
     private List<BigtableCell> getBigtableCells(@NotNull Row row) {
diff --git a/src/main/java/com/erikmafo/btviewer/sql/Field.java b/src/main/java/com/erikmafo/btviewer/sql/Field.java
index e406260..5ba7291 100644
--- a/src/main/java/com/erikmafo/btviewer/sql/Field.java
+++ b/src/main/java/com/erikmafo/btviewer/sql/Field.java
@@ -1,5 +1,8 @@
 package com.erikmafo.btviewer.sql;
 
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+
 import java.util.Objects;
 
 public class Field {
@@ -64,6 +67,8 @@ public int hashCode() {
         return Objects.hash(name);
     }
 
+    @NotNull
+    @Contract(pure = true)
     private String[] getFamilyAndQualifier() {
         return name.split("\\.");
     }
diff --git a/src/main/java/com/erikmafo/btviewer/sql/functions/AggregationExpression.java b/src/main/java/com/erikmafo/btviewer/sql/functions/AggregationExpression.java
index 4ca237f..57486e3 100644
--- a/src/main/java/com/erikmafo/btviewer/sql/functions/AggregationExpression.java
+++ b/src/main/java/com/erikmafo/btviewer/sql/functions/AggregationExpression.java
@@ -2,6 +2,7 @@
 
 import com.erikmafo.btviewer.sql.Field;
 import com.erikmafo.btviewer.sql.SqlToken;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Represents an aggregation of a field in a sql query.
@@ -26,7 +27,7 @@ public enum Type {
      * @return an {@link AggregationExpression}
      * @throws IllegalArgumentException if the sql token cannot be evaluated into an AggregationExpression.
      */
-    public static AggregationExpression from(SqlToken token) {
+    public static AggregationExpression from(@NotNull SqlToken token) {
         return AggregationExpressionParser.parse(token.getSubTokens());
     }
 
diff --git a/src/main/java/com/erikmafo/btviewer/ui/menubar/MenuBarController.java b/src/main/java/com/erikmafo/btviewer/ui/menubar/MenuBarController.java
index b1b0e57..195c356 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/menubar/MenuBarController.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/menubar/MenuBarController.java
@@ -12,6 +12,7 @@
 import javafx.scene.control.MenuBar;
 import javafx.scene.control.MenuItem;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import javax.inject.Inject;
 import java.nio.file.Path;
@@ -58,7 +59,7 @@ private void displaySpecifyCredentialsDialog(Path currentPath) {
                 .whenComplete(this::onCredentialsPathDialogComplete);
     }
 
-    private void onCredentialsPathDialogComplete(Path path, Throwable throwable) {
+    private void onCredentialsPathDialogComplete(@Nullable Path path, @Nullable Throwable throwable) {
         if (throwable != null) {
             displayError(throwable);
         }
diff --git a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/AddInstanceDialog.java b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/AddInstanceDialog.java
index cbf9fbc..23240b1 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/AddInstanceDialog.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/AddInstanceDialog.java
@@ -9,6 +9,7 @@
 import javafx.scene.control.TextField;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.concurrent.CompletableFuture;
 
@@ -30,7 +31,7 @@ public static CompletableFuture<BigtableInstance> displayAndAwaitResult() {
     }
 
     @NotNull
-    public static CompletableFuture<BigtableInstance> displayAndAwaitResult(String projectId) {
+    public static CompletableFuture<BigtableInstance> displayAndAwaitResult(@Nullable String projectId) {
         CompletableFuture<BigtableInstance> future = new CompletableFuture<>();
 
         Dialog<BigtableInstance> dialog = new Dialog<>();
diff --git a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/InstanceTreeItem.java b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/InstanceTreeItem.java
index a72648b..de45dd5 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/InstanceTreeItem.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/InstanceTreeItem.java
@@ -10,11 +10,12 @@
 
 public class InstanceTreeItem extends TreeItem<TreeItemData> {
 
+    @NotNull
     private final ListTablesService listTablesService;
     private boolean loadedChildren;
 
     @Inject
-    public InstanceTreeItem(ListTablesService listTablesService) {
+    public InstanceTreeItem(@NotNull ListTablesService listTablesService) {
         this.listTablesService = listTablesService;
         this.expandedProperty().addListener((observable, prev, isExpanded) -> {
             if (isExpanded && !loadedChildren && !listTablesService.isRunning()) {
diff --git a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/ProjectExplorerController.java b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/ProjectExplorerController.java
index fe8c167..c07911a 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/ProjectExplorerController.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/ProjectExplorerController.java
@@ -18,6 +18,7 @@
 import javafx.scene.control.TreeCell;
 import javafx.scene.control.TreeView;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import javax.inject.Inject;
 
@@ -31,7 +32,9 @@ public class ProjectExplorerController {
 
     private final Provider<RootTreeItem> rootTreeItemProvider;
 
+    @NotNull
     private final SimpleObjectProperty<BigtableTable> selectedTableProperty;
+    @NotNull
     private final SimpleObjectProperty<BigtableInstance> selectedInstanceProperty;
 
     private final SaveInstanceService saveInstanceService;
@@ -55,7 +58,7 @@ public void initialize() {
 
         treeView.setCellFactory(tableInfoTreeView -> new TreeCell<>() {
             @Override
-            protected void updateItem(TreeItemData item, boolean empty) {
+            protected void updateItem(@Nullable TreeItemData item, boolean empty) {
                 super.updateItem(item, empty);
                 if (empty || item == null) {
                     setText(null);
@@ -91,14 +94,17 @@ protected void updateItem(TreeItemData item, boolean empty) {
         addInstanceButton.setOnAction(this::handleAddInstanceAction);
     }
 
+    @NotNull
     public ReadOnlyObjectProperty<BigtableInstance> selectedInstanceProperty() {
         return selectedInstanceProperty;
     }
 
+    @NotNull
     public ReadOnlyObjectProperty<BigtableTable> selectedTableProperty() {
         return selectedTableProperty;
     }
 
+    @Nullable
     public ContextMenu createContextMenu(@NotNull TreeItemData item){
         ContextMenu menu = null;
         if (item.isProject()) {
@@ -129,7 +135,7 @@ private void handleAddInstanceAction(ActionEvent ignore) {
         AddInstanceDialog.displayAndAwaitResult().whenComplete(this::handleAddInstanceResult);
     }
 
-    private void handleAddInstanceResult(BigtableInstance instance, Throwable throwable) {
+    private void handleAddInstanceResult(@Nullable BigtableInstance instance, Throwable throwable) {
         if (instance == null) {
             return;
         }
diff --git a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/ProjectTreeItem.java b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/ProjectTreeItem.java
index bda5659..7fe9c45 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/ProjectTreeItem.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/ProjectTreeItem.java
@@ -12,13 +12,14 @@
 
 public class ProjectTreeItem extends TreeItem<TreeItemData> {
 
+    @NotNull
     private final LoadInstancesService loadInstancesService;
     private final Provider<InstanceTreeItem> instanceTreeItemProvider;
 
     private boolean loadedChildren;
 
     @Inject
-    public ProjectTreeItem(LoadInstancesService loadInstancesService,
+    public ProjectTreeItem(@NotNull LoadInstancesService loadInstancesService,
                            Provider<InstanceTreeItem> instanceTreeItemProvider) {
         this.loadInstancesService = loadInstancesService;
         this.instanceTreeItemProvider = instanceTreeItemProvider;
@@ -53,7 +54,7 @@ private void onLoadInstancesSucceeded(WorkerStateEvent event) {
     }
 
     @NotNull
-    private InstanceTreeItem createChild(TreeItemData treeItemData) {
+    private InstanceTreeItem createChild(@NotNull TreeItemData treeItemData) {
         var instanceItem = instanceTreeItemProvider.get();
         instanceItem.setValue(treeItemData);
         treeItemData.setTreeItem(instanceItem);
diff --git a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/RootTreeItem.java b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/RootTreeItem.java
index 59b4322..f27a2c8 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/RootTreeItem.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/RootTreeItem.java
@@ -11,12 +11,13 @@
 
 public class RootTreeItem extends TreeItem<TreeItemData> {
 
+    @NotNull
     private final LoadProjectsService loadProjectsService;
     private final Provider<ProjectTreeItem> projectTreeItemProvider;
 
     @Inject
     public RootTreeItem(
-            LoadProjectsService loadProjectsService,
+            @NotNull LoadProjectsService loadProjectsService,
             Provider<ProjectTreeItem> projectTreeItemProvider) {
         this.projectTreeItemProvider = projectTreeItemProvider;
         this.loadProjectsService = loadProjectsService;
@@ -44,7 +45,7 @@ public boolean isLeaf() {
         return false;
     }
 
-    private void loadChildren(LoadProjectsService loadProjectsService) {
+    private void loadChildren(@NotNull LoadProjectsService loadProjectsService) {
         this.loadProjectsService.setOnSucceeded(event -> {
             var children = loadProjectsService
                     .getValue()
diff --git a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/TreeItemData.java b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/TreeItemData.java
index 53f2721..c18bc1d 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/TreeItemData.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/projectexplorer/TreeItemData.java
@@ -8,6 +8,7 @@
 import javafx.beans.property.SimpleObjectProperty;
 import javafx.scene.control.TreeItem;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.Objects;
 
@@ -74,10 +75,12 @@ public String getDisplayName() {
         return displayName;
     }
 
+    @NotNull
     public BigtableTable toTable() {
         return new BigtableTable(projectId, instanceId, tableId);
     }
 
+    @NotNull
     public BigtableInstance toInstance() {
         return new BigtableInstance(projectId, instanceId);
     }
@@ -91,7 +94,7 @@ public String getInstanceId() {
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
 
@@ -114,6 +117,7 @@ public boolean isLoading() {
         return loading.get();
     }
 
+    @NotNull
     public BooleanProperty loadingProperty() {
         return loading;
     }
@@ -126,6 +130,7 @@ public TreeItem<TreeItemData> getTreeItem() {
         return treeItem.get();
     }
 
+    @NotNull
     public ObjectProperty<TreeItem<TreeItemData>> treeItemProperty() {
         return treeItem;
     }
diff --git a/src/main/java/com/erikmafo/btviewer/ui/querybox/QueryBoxController.java b/src/main/java/com/erikmafo/btviewer/ui/querybox/QueryBoxController.java
index d576c64..b544c8a 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/querybox/QueryBoxController.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/querybox/QueryBoxController.java
@@ -80,8 +80,10 @@ public void initialize() {
         bigtableQueryService.runningProperty().addListener((obs, wasRunning, isRunning) -> updateTimer(isRunning));
     }
 
+    @NotNull
     public ObjectProperty<BigtableTable> tableProperty() { return table; }
 
+    @NotNull
     public ObservableList<QueryResultRow> getQueryResult() { return queryResult; }
 
     public void setQuery(String sql) {
@@ -89,6 +91,7 @@ public void setQuery(String sql) {
         codeArea.replaceText(0, 0, sql);
     }
 
+    @NotNull
     public ObjectProperty<BigtableInstance> instanceProperty() {
         return instance;
     }
diff --git a/src/main/java/com/erikmafo/btviewer/ui/querybox/SyntaxHighlightingUtil.java b/src/main/java/com/erikmafo/btviewer/ui/querybox/SyntaxHighlightingUtil.java
index 8bf64ba..2846d2f 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/querybox/SyntaxHighlightingUtil.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/querybox/SyntaxHighlightingUtil.java
@@ -20,7 +20,7 @@ public class SyntaxHighlightingUtil {
     private static final String FUNCTION_STYLE_CLASS = "function";
     private static final String OPERATOR_STYLE_CLASS = "logical-operator";
 
-    public static StyleSpans<Collection<String>> computeSyntaxHighlighting(String queryText) {
+    public static StyleSpans<Collection<String>> computeSyntaxHighlighting(@NotNull String queryText) {
         var sqlTokenizer = new SqlTokenizer(queryText);
         var token = sqlTokenizer.next();
         int lastHighlightEnd = 0;
@@ -35,7 +35,7 @@ public static StyleSpans<Collection<String>> computeSyntaxHighlighting(String qu
         return spansBuilder.create();
     }
 
-    private static int applyStyleClass(SqlToken token, int lastHighlightEnd, StyleSpansBuilder<Collection<String>> spansBuilder) {
+    private static int applyStyleClass(@NotNull SqlToken token, int lastHighlightEnd, @NotNull StyleSpansBuilder<Collection<String>> spansBuilder) {
         var styleClass = getStyleClass(token);
         if (styleClass != null) {
             spansBuilder.add(Collections.emptyList(), token.getStart() - lastHighlightEnd);
@@ -46,7 +46,7 @@ private static int applyStyleClass(SqlToken token, int lastHighlightEnd, StyleSp
     }
 
     @NotNull
-    private static List<SqlToken> getTokenAndSubTokens(SqlToken token) {
+    private static List<SqlToken> getTokenAndSubTokens(@NotNull SqlToken token) {
         var tokens = new ArrayList<SqlToken>();
         tokens.add(token);
         if (token.getSubTokens() != null) {
diff --git a/src/main/java/com/erikmafo/btviewer/ui/queryresult/CellView.java b/src/main/java/com/erikmafo/btviewer/ui/queryresult/CellView.java
index 2d6c4cd..7471050 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/queryresult/CellView.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/queryresult/CellView.java
@@ -11,6 +11,7 @@
 import javafx.fxml.FXML;
 import javafx.scene.control.Label;
 import javafx.scene.layout.BorderPane;
+import org.jetbrains.annotations.NotNull;
 
 import java.time.Instant;
 import java.time.ZoneId;
@@ -53,10 +54,12 @@ public boolean getDisplayTimestamp() {
         return displayTimestamp.get();
     }
 
+    @NotNull
     public BooleanProperty displayTimestampProperty() {
         return displayTimestamp;
     }
 
+    @NotNull
     public ObjectProperty<BigtableValueConverter> valueConverterProperty() { return valueConverter; }
 
     private String getDisplayValue() {
diff --git a/src/main/java/com/erikmafo/btviewer/ui/queryresult/QueryResultViewController.java b/src/main/java/com/erikmafo/btviewer/ui/queryresult/QueryResultViewController.java
index 0862392..358942e 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/queryresult/QueryResultViewController.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/queryresult/QueryResultViewController.java
@@ -39,6 +39,7 @@
 import javafx.scene.layout.VBox;
 import javafx.util.Callback;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import javax.inject.Inject;
 import java.util.Collections;
@@ -61,6 +62,7 @@ public class QueryResultViewController {
     @FXML
     private TreeTableView<QueryResultRow> tableView;
 
+    @Nullable
     private final BigtableRowTreeItem root;
 
     private final SimpleObjectProperty<BigtableTable> table = new SimpleObjectProperty<>();
@@ -106,7 +108,7 @@ public void handleTableSettingsButtonPressed(ActionEvent actionEvent) {
     }
 
     @FXML
-    public void onTableViewKeyPressed(KeyEvent keyEvent) {
+    public void onTableViewKeyPressed(@NotNull KeyEvent keyEvent) {
         if (isCopyOperation(keyEvent)) {
             copySelectedCellsToClipboard();
         }
@@ -126,6 +128,7 @@ public void setRows(@NotNull ObservableList<QueryResultRow> rows) {
         rows.addListener(this::onBigtableRowsChange);
     }
 
+    @NotNull
     public SimpleObjectProperty<BigtableTable> tableProperty() {
         return table;
     }
@@ -142,7 +145,7 @@ private void onBigtableRowsChange(@NotNull ListChangeListener.Change<? extends Q
         root.getChildren().setAll(treeItems);
     }
 
-    private boolean isCopyOperation(KeyEvent keyEvent) {
+    private boolean isCopyOperation(@NotNull KeyEvent keyEvent) {
         return PlatformUtil.isMac() ?
                 keyEvent.getCode() == KeyCode.C && keyEvent.isMetaDown() :
                 keyEvent.getCode() == KeyCode.C && keyEvent.isControlDown();
@@ -237,7 +240,7 @@ private TreeTableColumn<QueryResultRow, BigtableCell> getQualifierTableColumn(St
                 .orElse(null);
     }
 
-    private void updateTableConfiguration(BigtableTable table, BigtableTableSettings configuration) {
+    private void updateTableConfiguration(BigtableTable table, @Nullable BigtableTableSettings configuration) {
         if (configuration == null) {
             return;
         }
@@ -284,6 +287,7 @@ private static class CellValueFactory implements Callback<TreeTableColumn.CellDa
             this.qualifier = qualifier;
         }
 
+        @NotNull
         @Override
         public ObservableValue<BigtableCell> call(@NotNull TreeTableColumn.CellDataFeatures<QueryResultRow, BigtableCell> param) {
             return new ReadOnlyObjectWrapper<>(param.getValue().getValue().getLatestCell(family, qualifier));
@@ -292,6 +296,7 @@ public ObservableValue<BigtableCell> call(@NotNull TreeTableColumn.CellDataFeatu
 
     private static class RowKeyTableCellFactory implements Callback<TreeTableColumn<QueryResultRow, String>, TreeTableCell<QueryResultRow, String>> {
 
+        @NotNull
         @Override
         public TreeTableCell<QueryResultRow, String> call(TreeTableColumn<QueryResultRow, String> column) {
             return new TreeTableCell<>() {
@@ -312,6 +317,7 @@ protected void updateItem(String rowKey, boolean empty) {
 
     private class CellFactory implements Callback<TreeTableColumn<QueryResultRow, BigtableCell>, TreeTableCell<QueryResultRow, BigtableCell>>
     {
+        @NotNull
         @Override
         public TreeTableCell<QueryResultRow, BigtableCell> call(TreeTableColumn<QueryResultRow, BigtableCell> column) {
             return new TreeTableCell<>() {
diff --git a/src/main/java/com/erikmafo/btviewer/ui/shared/CredentialsPathDialog.java b/src/main/java/com/erikmafo/btviewer/ui/shared/CredentialsPathDialog.java
index d995144..0ef7234 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/shared/CredentialsPathDialog.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/shared/CredentialsPathDialog.java
@@ -10,6 +10,7 @@
 import javafx.scene.control.TextField;
 import javafx.stage.FileChooser;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.nio.file.Files;
 import java.nio.file.InvalidPathException;
@@ -29,7 +30,7 @@ public CredentialsPathDialog() {
     }
 
     @NotNull
-    public static CompletableFuture<Path> displayAndAwaitResult(Path currentPath) {
+    public static CompletableFuture<Path> displayAndAwaitResult(@Nullable Path currentPath) {
         CompletableFuture<Path> result = new CompletableFuture<>();
         Dialog<String> dialog = new Dialog<>();
         var credentialsPathDialog = new CredentialsPathDialog();
@@ -68,7 +69,7 @@ public void handleEditCredentialsPathAction(ActionEvent event) {
         }
     }
 
-    private static boolean validatePath(String pathAsString) {
+    private static boolean validatePath(@Nullable String pathAsString) {
         if (pathAsString == null) {
             return false;
         }
diff --git a/src/main/java/com/erikmafo/btviewer/ui/shared/TableSettingsDialog.java b/src/main/java/com/erikmafo/btviewer/ui/shared/TableSettingsDialog.java
index d328757..59c4449 100644
--- a/src/main/java/com/erikmafo/btviewer/ui/shared/TableSettingsDialog.java
+++ b/src/main/java/com/erikmafo/btviewer/ui/shared/TableSettingsDialog.java
@@ -16,6 +16,7 @@
 import javafx.scene.layout.GridPane;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -42,7 +43,7 @@ private TableSettingsDialog() {
     @NotNull
     public static CompletableFuture<BigtableTableSettings> displayAndAwaitResult(
             @NotNull List<BigtableColumn> columns,
-            BigtableTableSettings currentSettings) {
+            @Nullable BigtableTableSettings currentSettings) {
 
         var settings = currentSettings != null ? currentSettings : new BigtableTableSettings();
         CompletableFuture<BigtableTableSettings> future = new CompletableFuture<>();
@@ -97,7 +98,7 @@ private void addSchemaRow() {
         addSchemaRow(new BigtableColumn("", ""));
     }
 
-    private void addSchemaRow(BigtableColumn column) {
+    private void addSchemaRow(@NotNull BigtableColumn column) {
         addSchemaRow(column, null);
     }
 
@@ -106,7 +107,7 @@ private void addSchemaRow(@NotNull CellDefinition cellDefinition) {
                 cellDefinition.getFamily(), cellDefinition.getQualifier()), cellDefinition.getValueType());
     }
 
-    private void addSchemaRow(BigtableColumn column, String valueType) {
+    private void addSchemaRow(@NotNull BigtableColumn column, @Nullable String valueType) {
         var alreadyAdded = observableCells.stream().anyMatch(cell ->
                 cell.getFamily().equals(column.getFamily()) &&
                 cell.getQualifier().equals(column.getQualifier()));
@@ -141,6 +142,7 @@ public String getValueType() {
             return valueType.get();
         }
 
+        @NotNull
         public StringProperty valueTypeProperty() {
             return valueType;
         }
@@ -153,6 +155,7 @@ public String getFamily() {
             return family.get();
         }
 
+        @NotNull
         public StringProperty familyProperty() {
             return family;
         }
@@ -165,6 +168,7 @@ public String getQualifier() {
             return qualifier.get();
         }
 
+        @NotNull
         public StringProperty qualifierProperty() {
             return qualifier;
         }