diff --git a/src/main/java/spoon/support/adaption/TypeAdaptor.java b/src/main/java/spoon/support/adaption/TypeAdaptor.java
index 34bac74c489..a214df4a334 100644
--- a/src/main/java/spoon/support/adaption/TypeAdaptor.java
+++ b/src/main/java/spoon/support/adaption/TypeAdaptor.java
@@ -450,13 +450,17 @@ public boolean isOverriding(CtMethod<?> subMethod, CtMethod<?> superMethod) {
 		if (!isSubtype(subDeclaringType, superDeclaringType.getReference())) {
 			return false;
 		}
-
+		// we lock here because of multi threading issues, see https://github.com/INRIA/spoon/issues/5619
+		CtMethod<?> adapted;
 		// We don't need to clone the body here, so leave it out
-		CtBlock<?> superBody = superMethod.getBody();
-		superMethod.setBody(null);
-		CtMethod<?> adapted = new TypeAdaptor(subMethod.getDeclaringType())
-			.adaptMethod(superMethod);
-		superMethod.setBody(superBody);
+		synchronized (superMethod) {
+			CtBlock<?> superBody = superMethod.getBody();
+			superBody.clone();
+			superMethod.setBody(null);
+			adapted = new TypeAdaptor(subMethod.getDeclaringType())
+					.adaptMethod(superMethod);
+			superMethod.setBody(superBody);
+		}
 
 		for (int i = 0; i < subMethod.getParameters().size(); i++) {
 			CtParameter<?> subParam = subMethod.getParameters().get(i);