diff --git a/j2k/src/org/jetbrains/kotlin/j2k/TypeVisitor.kt b/j2k/src/org/jetbrains/kotlin/j2k/TypeVisitor.kt
index 75c302700ef..aae370235e1 100644
--- a/j2k/src/org/jetbrains/kotlin/j2k/TypeVisitor.kt
+++ b/j2k/src/org/jetbrains/kotlin/j2k/TypeVisitor.kt
@@ -34,6 +34,9 @@ class TypeVisitor(
 
     private val typeConverter: TypeConverter = converter.typeConverter
 
+    //TODO: support for all types
+    override fun visitType(type: PsiType) = ErrorType()
+
     override fun visitPrimitiveType(primitiveType: PsiPrimitiveType): Type {
         val name = primitiveType.getCanonicalText()
         return if (name == "void") {
diff --git a/j2k/src/org/jetbrains/kotlin/j2k/ast/Types.kt b/j2k/src/org/jetbrains/kotlin/j2k/ast/Types.kt
index b60e7d72c7c..31788911a20 100644
--- a/j2k/src/org/jetbrains/kotlin/j2k/ast/Types.kt
+++ b/j2k/src/org/jetbrains/kotlin/j2k/ast/Types.kt
@@ -76,18 +76,18 @@ class UnitType : NotNullType() {
     }
 }
 
-class NullType : Type() {
-    override val isNullable: Boolean = true
-
+open class ErrorType : Type() {
     override fun generateCode(builder: CodeBuilder) {
         builder.append("???")
     }
+
+    override val isNullable: Boolean
+        get() = false
 }
 
-class ErrorType : NotNullType() {
-    override fun generateCode(builder: CodeBuilder) {
-        builder.append("UNRESOLVED_TYPE")
-    }
+class NullType : ErrorType() {
+    override val isNullable: Boolean
+        get() = true
 }
 
 class ClassType(val referenceElement: ReferenceElement, nullability: Nullability, settings: ConverterSettings)