diff --git a/src/org/jetbrains/jet/j2k/visitors/ClassVisitor.java b/src/org/jetbrains/jet/j2k/visitors/ClassVisitor.java
deleted file mode 100644
index 49816e40dd1..00000000000
--- a/src/org/jetbrains/jet/j2k/visitors/ClassVisitor.java
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * Copyright 2010-2012 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.jetbrains.jet.j2k.visitors;
-
-import com.intellij.psi.JavaRecursiveElementVisitor;
-import com.intellij.psi.PsiClass;
-import org.jetbrains.annotations.NotNull;
-
-import java.util.HashSet;
-import java.util.Set;
-
-/**
- * @author ignatov
- */
-public class ClassVisitor extends JavaRecursiveElementVisitor {
-    private final Set<String> myClassIdentifiers;
-
-    public ClassVisitor() {
-        myClassIdentifiers = new HashSet<String>();
-    }
-
-    @NotNull
-    public Set<String> getClassIdentifiers() {
-        return new HashSet<String>(myClassIdentifiers);
-    }
-
-    @Override
-    public void visitClass(@NotNull PsiClass aClass) {
-        myClassIdentifiers.add(aClass.getQualifiedName());
-        super.visitClass(aClass);
-    }
-}
diff --git a/src/org/jetbrains/jet/j2k/visitors/ClassVisitor.kt b/src/org/jetbrains/jet/j2k/visitors/ClassVisitor.kt
new file mode 100644
index 00000000000..4697aaac28d
--- /dev/null
+++ b/src/org/jetbrains/jet/j2k/visitors/ClassVisitor.kt
@@ -0,0 +1,18 @@
+package org.jetbrains.jet.j2k.visitors
+
+import com.intellij.psi.JavaRecursiveElementVisitor
+import com.intellij.psi.PsiClass
+import java.util.HashSet
+import java.util.Set
+
+public open class ClassVisitor(): JavaRecursiveElementVisitor() {
+    private val myClassIdentifiers: Set<String> = HashSet<String>()
+    public open fun getClassIdentifiers(): Set<String> {
+        return HashSet<String>(myClassIdentifiers)
+    }
+
+    public override fun visitClass(aClass: PsiClass?): Unit {
+        myClassIdentifiers.add(aClass?.getQualifiedName()!!)
+        super.visitClass(aClass)
+    }
+}