diff --git a/java/java-impl/src/com/intellij/pom/java/AcceptedLanguageLevelsSettings.java b/java/java-impl/src/com/intellij/pom/java/AcceptedLanguageLevelsSettings.java
index a28da92c95ca..a4de8150fa0a 100644
--- a/java/java-impl/src/com/intellij/pom/java/AcceptedLanguageLevelsSettings.java
+++ b/java/java-impl/src/com/intellij/pom/java/AcceptedLanguageLevelsSettings.java
@@ -153,7 +153,7 @@ public final class AcceptedLanguageLevelsSettings implements PersistentStateComp
     if (ApplicationManager.getApplication().isEAP()) return true;
     // language levels up to HIGHEST are officially supported
     var nonPreviewLevel = languageLevel.getNonPreviewLevel();
-    return nonPreviewLevel != null && JavaRelease.getHighest().compareTo(nonPreviewLevel) >= 0 || getSettings().acceptedNames.contains(languageLevel.name());
+    return JavaRelease.getHighest().compareTo(nonPreviewLevel) >= 0 || getSettings().acceptedNames.contains(languageLevel.name());
   }
 
   private static void acceptAndRestore(Project project, Collection<? extends Module> modules, LanguageLevel languageLevel) {
diff --git a/java/java-syntax/src/com/intellij/pom/java/LanguageLevel.kt b/java/java-syntax/src/com/intellij/pom/java/LanguageLevel.kt
index bf0dcf5241e8..9e8a7ca1c5c7 100644
--- a/java/java-syntax/src/com/intellij/pom/java/LanguageLevel.kt
+++ b/java/java-syntax/src/com/intellij/pom/java/LanguageLevel.kt
@@ -123,11 +123,11 @@ enum class LanguageLevel {
   }
 
   /**
-   * @return corresponding non-preview level, `this` if this level is non-preview already, `null` if the level is unreleased and unsupported
+   * @return corresponding non-preview level, `this` for [JDK_X] and non-preview levels.
    */
-  fun getNonPreviewLevel(): LanguageLevel? {
-    if (!isPreview) return this
-    return ourStandardVersions[myVersion.feature]
+  fun getNonPreviewLevel(): LanguageLevel {
+    if (!isPreview || this == JDK_X) return this
+    return requireNotNull(ourStandardVersions[myVersion.feature])
   }
 
   val presentableText: @Nls String
diff --git a/plugins/gradle/java/testSources/importing/GradleJavaCompilerSettingsImportingTest.kt b/plugins/gradle/java/testSources/importing/GradleJavaCompilerSettingsImportingTest.kt
index 97fbdb085f3e..a203efa2bfd1 100644
--- a/plugins/gradle/java/testSources/importing/GradleJavaCompilerSettingsImportingTest.kt
+++ b/plugins/gradle/java/testSources/importing/GradleJavaCompilerSettingsImportingTest.kt
@@ -99,7 +99,7 @@ class GradleJavaCompilerSettingsImportingTest : GradleJavaCompilerSettingsImport
   @Test
   fun `test language level approximation`() {
     val highest = JavaRelease.getHighest()
-    val nonPreview = highest.getNonPreviewLevel()!!
+    val nonPreview = highest.getNonPreviewLevel()
     val preview = nonPreview.getPreviewLevel()
 
     Assume.assumeTrue("The IDE $highest Java version doesn't have preview level",