diff --git a/j2k/newSrc/org/jetbrains/kotlin/j2k/JavaToJKTreeBuilder.kt b/j2k/newSrc/org/jetbrains/kotlin/j2k/JavaToJKTreeBuilder.kt
index ca748529833..30e19a64592 100644
--- a/j2k/newSrc/org/jetbrains/kotlin/j2k/JavaToJKTreeBuilder.kt
+++ b/j2k/newSrc/org/jetbrains/kotlin/j2k/JavaToJKTreeBuilder.kt
@@ -362,7 +362,7 @@ class JavaToJKTreeBuilder(var symbolProvider: JKSymbolProvider) {
 
         fun PsiTypeParameter.toJK(): JKTypeParameter =
             JKTypeParameterImpl(JKNameIdentifierImpl(name!!),
-                                extendsListTypes.map { JKTypeElementImpl(it.toJK(symbolProvider, Nullability.NotNull)) })
+                                extendsListTypes.map { JKTypeElementImpl(it.toJK(symbolProvider, Nullability.Default)) })
 
         fun PsiClass.toJK(): JKClass {
             val classKind: JKClass.ClassKind = when {
@@ -373,7 +373,7 @@ class JavaToJKTreeBuilder(var symbolProvider: JKSymbolProvider) {
             }
 
             fun PsiReferenceList.mapTypes() =
-                this.referencedTypes.map { with(expressionTreeMapper) { JKTypeElementImpl(it.toJK(symbolProvider, Nullability.NotNull)) } }
+                this.referencedTypes.map { with(expressionTreeMapper) { JKTypeElementImpl(it.toJK(symbolProvider, Nullability.Default)) } }
 
             val implTypes = this.implementsList?.mapTypes().orEmpty()
             val extensionType = this.extendsList?.mapTypes().orEmpty()
diff --git a/j2k/newSrc/org/jetbrains/kotlin/j2k/conversions/LowerNullabilityInFunctionParametersConversion.kt b/j2k/newSrc/org/jetbrains/kotlin/j2k/conversions/LowerNullabilityInFunctionParametersConversion.kt
index 0ba5415c637..bce218a0445 100644
--- a/j2k/newSrc/org/jetbrains/kotlin/j2k/conversions/LowerNullabilityInFunctionParametersConversion.kt
+++ b/j2k/newSrc/org/jetbrains/kotlin/j2k/conversions/LowerNullabilityInFunctionParametersConversion.kt
@@ -5,12 +5,11 @@
 
 package org.jetbrains.kotlin.j2k.conversions
 
-import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.j2k.ConversionContext
 import org.jetbrains.kotlin.j2k.ast.Nullability
 import org.jetbrains.kotlin.j2k.tree.*
-import org.jetbrains.kotlin.j2k.tree.impl.*
-import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.j2k.tree.impl.JKFieldSymbol
+import org.jetbrains.kotlin.j2k.tree.impl.JKTypeElementImpl
 
 class LowerNullabilityInFunctionParametersConversion(private val context: ConversionContext) : RecursiveApplicableConversionBase() {
     override fun applyToElement(element: JKTreeElement): JKTreeElement {
@@ -21,7 +20,7 @@ class LowerNullabilityInFunctionParametersConversion(private val context: Conver
                 (element as? JKKtConstructor)?.delegationCall
             )
         for (parameter in element.parameters) {
-            if (parameter.type.type.nullability == Nullability.NotNull) continue
+            if (parameter.type.type.nullability != Nullability.Default) continue
             if (parameter.hasNotNullUsages(scopes)) {
                 parameter.type = JKTypeElementImpl(parameter.type.type.updateNullability(Nullability.NotNull))
             }