diff --git a/AlgebraicDataflowArchitectureModel/src/application/ApplicationWindow.java b/AlgebraicDataflowArchitectureModel/src/application/ApplicationWindow.java
index bfc4f3c..8983a22 100644
--- a/AlgebraicDataflowArchitectureModel/src/application/ApplicationWindow.java
+++ b/AlgebraicDataflowArchitectureModel/src/application/ApplicationWindow.java
@@ -14,13 +14,13 @@
 	private static final long serialVersionUID = -8690140317781055614L;
 	public static final String title = "Visual Modeling Tool";
 	
-	private Editor editor = null;
-	private mxGraph graph = null;
-	private mxGraphComponent graphComponent = null;
+	private Editor editor;
+	private final mxGraph graph;
+	private final mxGraphComponent graphComponent;
 	
-	private ApplicationMenuBar menuBar = null;
-	private NavigationWindow navigationWindow;
-	private FlowLayerWindow showFlowLayerWindow = null;
+	private final ApplicationMenuBar menuBar;
+	private final NavigationWindow navigationWindow;
+	private final FlowLayerWindow showFlowLayerWindow;
 	
 	public ApplicationWindow() {
 		setTitle(title);