diff --git a/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/spring/SpringContextScanner.java b/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/spring/SpringContextScanner.java
index 79a79ea..5d19c92 100644
--- a/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/spring/SpringContextScanner.java
+++ b/state_machine_exporter/src/main/java/click/kamil/springstatemachineexporter/analysis/spring/SpringContextScanner.java
@@ -142,12 +142,25 @@ public class SpringContextScanner extends ASTVisitor {
 
     private void collectAssignableTypes(ITypeBinding binding, Set<String> types) {
         if (binding == null) return;
-        types.add(binding.getQualifiedName());
-        types.add(binding.getErasure().getQualifiedName()); // Handles generics (e.g., List<String> -> List)
+        
+        String qName = binding.getQualifiedName();
+        if (qName != null && !qName.isEmpty()) {
+            types.add(qName);
+        }
+        
+        ITypeBinding erasure = binding.getErasure();
+        if (erasure != null) {
+            String erasureName = erasure.getQualifiedName();
+            if (erasureName != null && !erasureName.isEmpty()) {
+                types.add(erasureName);
+            }
+        }
 
         collectAssignableTypes(binding.getSuperclass(), types);
-        for (ITypeBinding iface : binding.getInterfaces()) {
-            collectAssignableTypes(iface, types);
+        if (binding.getInterfaces() != null) {
+            for (ITypeBinding iface : binding.getInterfaces()) {
+                collectAssignableTypes(iface, types);
+            }
         }
     }