diff --git a/src/main/java/click/kamil/callgraphexporter/JdtResolvedCallGraph.java b/src/main/java/click/kamil/callgraphexporter/JdtResolvedCallGraph.java
index e307a97..08b9a8e 100644
--- a/src/main/java/click/kamil/callgraphexporter/JdtResolvedCallGraph.java
+++ b/src/main/java/click/kamil/callgraphexporter/JdtResolvedCallGraph.java
@@ -1,5 +1,8 @@
 package click.kamil.callgraphexporter;
 
+import click.kamil.callgraphexporter.domain.MethodMetadata;
+import click.kamil.callgraphexporter.domain.MethodSignature;
+import click.kamil.callgraphexporter.domain.Modifiers;
 import org.eclipse.jdt.core.JavaCore;
 import org.eclipse.jdt.core.dom.*;
 
@@ -93,9 +96,8 @@ public class JdtResolvedCallGraph {
         });
     }
 
+    // Fixed: matches your MethodSignature record with only methodName and paramTypes
     private static MethodSignature toSignature(IMethodBinding binding) {
-        String packageName = binding.getDeclaringClass().getPackage().getName();
-        String className = binding.getDeclaringClass().getName();
         String methodName = binding.getName();
 
         List<String> paramTypes = new ArrayList<>();
@@ -103,7 +105,7 @@ public class JdtResolvedCallGraph {
             paramTypes.add(param.getName());
         }
 
-        return new MethodSignature(packageName, className, methodName, paramTypes);
+        return new MethodSignature(methodName, paramTypes);
     }
 
     private static MethodMetadata toMetadata(IMethodBinding binding, MethodDeclaration method) {
@@ -123,18 +125,25 @@ public class JdtResolvedCallGraph {
     private static void generateDotFile(String filename) throws IOException {
         StringBuilder sb = new StringBuilder("digraph G {\n");
         for (MethodSignature caller : callGraph.keySet()) {
+            String callerLabel = formatSignature(caller);
             for (MethodSignature callee : callGraph.get(caller)) {
-                sb.append("  \"").append(caller).append("\" -> \"").append(callee).append("\";\n");
+                String calleeLabel = formatSignature(callee);
+                sb.append("  \"").append(callerLabel).append("\" -> \"").append(calleeLabel).append("\";\n");
             }
         }
         sb.append("}");
         Files.writeString(new File(filename).toPath(), sb.toString());
     }
+
+    private static String formatSignature(MethodSignature sig) {
+        // Build a readable label (methodName + param list)
+        return sig.methodName() + sig.parameterTypes();
+    }
+
     private static Set<Modifiers> extractModifiers(IMethodBinding binding, MethodDeclaration method) {
         Set<Modifiers> result = new HashSet<>();
         int mods = binding.getModifiers();
 
-        // 1. From bitmask
         if (Modifier.isPublic(mods))        result.add(Modifiers.PUBLIC);
         if (Modifier.isPrivate(mods))       result.add(Modifiers.PRIVATE);
         if (Modifier.isProtected(mods))     result.add(Modifiers.PROTECTED);
@@ -145,13 +154,10 @@ public class JdtResolvedCallGraph {
         if (Modifier.isSynchronized(mods))  result.add(Modifiers.SYNCHRONIZED);
         if (Modifier.isStrictfp(mods))      result.add(Modifiers.STRICTFP);
 
-        // 2. From modifiers list for special cases
         for (Object mod : method.modifiers()) {
             if (mod instanceof Modifier keyword) {
                 if (keyword.isDefault()) result.add(Modifiers.DEFAULT);
-                // NOTE: isSealed and isNonSealed are class-level only
             }
-            // If needed, check for annotation modifiers here
         }
 
         return result;
diff --git a/src/main/java/click/kamil/callgraphexporter/Method.java b/src/main/java/click/kamil/callgraphexporter/domain/Method.java
similarity index 85%
rename from src/main/java/click/kamil/callgraphexporter/Method.java
rename to src/main/java/click/kamil/callgraphexporter/domain/Method.java
index 415ef24..6e34adf 100644
--- a/src/main/java/click/kamil/callgraphexporter/Method.java
+++ b/src/main/java/click/kamil/callgraphexporter/domain/Method.java
@@ -1,4 +1,4 @@
-package click.kamil.callgraphexporter;
+package click.kamil.callgraphexporter.domain;
 
 import lombok.AllArgsConstructor;
 import lombok.Getter;
diff --git a/src/main/java/click/kamil/callgraphexporter/MethodMetadata.java b/src/main/java/click/kamil/callgraphexporter/domain/MethodMetadata.java
similarity index 85%
rename from src/main/java/click/kamil/callgraphexporter/MethodMetadata.java
rename to src/main/java/click/kamil/callgraphexporter/domain/MethodMetadata.java
index 237b6d9..241a23c 100644
--- a/src/main/java/click/kamil/callgraphexporter/MethodMetadata.java
+++ b/src/main/java/click/kamil/callgraphexporter/domain/MethodMetadata.java
@@ -1,4 +1,4 @@
-package click.kamil.callgraphexporter;
+package click.kamil.callgraphexporter.domain;
 
 import java.util.List;
 import java.util.Set;
diff --git a/src/main/java/click/kamil/callgraphexporter/MethodSignature.java b/src/main/java/click/kamil/callgraphexporter/domain/MethodSignature.java
similarity index 57%
rename from src/main/java/click/kamil/callgraphexporter/MethodSignature.java
rename to src/main/java/click/kamil/callgraphexporter/domain/MethodSignature.java
index f0e7630..dd7f275 100644
--- a/src/main/java/click/kamil/callgraphexporter/MethodSignature.java
+++ b/src/main/java/click/kamil/callgraphexporter/domain/MethodSignature.java
@@ -1,10 +1,8 @@
-package click.kamil.callgraphexporter;
+package click.kamil.callgraphexporter.domain;
 
 import java.util.List;
 
 public record MethodSignature(
-        String packageName,
-        String className,
         String methodName,
         List<String> parameterTypes
 ) {
diff --git a/src/main/java/click/kamil/callgraphexporter/Modifiers.java b/src/main/java/click/kamil/callgraphexporter/domain/Modifiers.java
similarity index 82%
rename from src/main/java/click/kamil/callgraphexporter/Modifiers.java
rename to src/main/java/click/kamil/callgraphexporter/domain/Modifiers.java
index 36e9a1a..9090284 100644
--- a/src/main/java/click/kamil/callgraphexporter/Modifiers.java
+++ b/src/main/java/click/kamil/callgraphexporter/domain/Modifiers.java
@@ -1,4 +1,4 @@
-package click.kamil.callgraphexporter;
+package click.kamil.callgraphexporter.domain;
 
 public enum Modifiers {
     PUBLIC,
@@ -16,4 +16,3 @@ public enum Modifiers {
     SEALED,
     NON_SEALED,
 }
-
diff --git a/src/main/java/click/kamil/callgraphexporter/domain/TypeGroup.java b/src/main/java/click/kamil/callgraphexporter/domain/TypeGroup.java
new file mode 100644
index 0000000..3b84adb
--- /dev/null
+++ b/src/main/java/click/kamil/callgraphexporter/domain/TypeGroup.java
@@ -0,0 +1,26 @@
+package click.kamil.callgraphexporter.domain;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+import java.util.ArrayList;
+import java.util.EnumSet;
+import java.util.List;
+
+@Getter
+@Setter
+@AllArgsConstructor
+@NoArgsConstructor
+public class TypeGroup {
+    private String packageName;
+    private String typeName;
+    private TypeKind typeKind;
+    private EnumSet<Modifiers> modifiers = EnumSet.noneOf(Modifiers.class);
+    private List<Method> methods = new ArrayList<>();
+
+    public void addMethod(Method method) {
+        methods.add(method);
+    }
+}
diff --git a/src/main/java/click/kamil/callgraphexporter/domain/TypeKind.java b/src/main/java/click/kamil/callgraphexporter/domain/TypeKind.java
new file mode 100644
index 0000000..966166d
--- /dev/null
+++ b/src/main/java/click/kamil/callgraphexporter/domain/TypeKind.java
@@ -0,0 +1,9 @@
+package click.kamil.callgraphexporter.domain;
+
+public enum TypeKind {
+    CLASS,
+    INTERFACE,
+    RECORD,
+    ENUM,
+    ANNOTATION
+}
diff --git a/src/main/java/click/kamil/filecombine/JavaConcatenator.java b/src/main/java/click/kamil/filecombine/JavaConcatenator.java
index 4dd7d19..da4ab12 100644
--- a/src/main/java/click/kamil/filecombine/JavaConcatenator.java
+++ b/src/main/java/click/kamil/filecombine/JavaConcatenator.java
@@ -14,7 +14,7 @@ import java.util.*;
 public class JavaConcatenator {
 
     public static void main(String[] args) throws IOException {
-        Path sourceDir = Path.of("./src/main/java/click/kamil/springstatemachineexporter/ast");
+        Path sourceDir = Path.of("./src/main/java/click/kamil/callgraphexporter/domain");
         Path outputFile = Path.of("./Combined.java");
 
         String targetPackage = "click.kamil";