diff --git a/src/main/java/org/jastadd/tooling/aspect/JavaBlockLanguageInjector.java b/src/main/java/org/jastadd/tooling/aspect/JavaBlockLanguageInjector.java
index 298ea5999a6675a61912208090b47e614daf400b..57c731758e6173e4ecdc0dc41819d57f6baa4c44 100644
--- a/src/main/java/org/jastadd/tooling/aspect/JavaBlockLanguageInjector.java
+++ b/src/main/java/org/jastadd/tooling/aspect/JavaBlockLanguageInjector.java
@@ -6,6 +6,7 @@ import com.intellij.openapi.util.TextRange;
 import com.intellij.psi.InjectedLanguagePlaces;
 import com.intellij.psi.LanguageInjector;
 import com.intellij.psi.PsiLanguageInjectionHost;
+import org.jastadd.tooling.aspect.psi.JastAddAspectJavaBlock;
 import org.jetbrains.annotations.NotNull;
 
 public class JavaBlockLanguageInjector implements LanguageInjector {
@@ -20,6 +21,9 @@ public class JavaBlockLanguageInjector implements LanguageInjector {
    */
   @Override
   public void getLanguagesToInject(@NotNull PsiLanguageInjectionHost host, @NotNull InjectedLanguagePlaces injectionPlacesRegistrar) {
-    injectionPlacesRegistrar.addPlace(JavaLanguage.INSTANCE, new TextRange(0, host.getTextLength()), "class X { public void m(){", "}");
+    if (host.isValidHost() && host instanceof JastAddAspectJavaBlock) {
+      System.out.println(host.getText());
+      injectionPlacesRegistrar.addPlace(JavaLanguage.INSTANCE, new TextRange(0, host.getTextLength()), "class X { public void m(){", "}");
+    }
   }
 }