diff --git a/compiler/testData/builtin-classes/newMethods/kotlin.txt b/compiler/testData/builtin-classes/newMethods/kotlin.txt
index 2bb26a0b6aa..01b1737c826 100644
--- a/compiler/testData/builtin-classes/newMethods/kotlin.txt
+++ b/compiler/testData/builtin-classes/newMethods/kotlin.txt
@@ -744,6 +744,9 @@ public final class String : kotlin.Comparable<kotlin.String>, kotlin.CharSequenc
     public open override /*1*/ fun compareTo(/*0*/ other: kotlin.String): kotlin.Int
     public open override /*1*/ fun get(/*0*/ index: kotlin.Int): kotlin.Char
     public final operator fun plus(/*0*/ other: kotlin.Any?): kotlin.String
+    @kotlin.Deprecated(level = DeprecationLevel.WARNING, message = "This member is not fully supported by Kotlin compiler, so it may be absent or have different signature in next major version", replaceWith = kotlin.ReplaceWith(expression = "", imports = {})) public open fun strip(): kotlin.String!
+    @kotlin.Deprecated(level = DeprecationLevel.WARNING, message = "This member is not fully supported by Kotlin compiler, so it may be absent or have different signature in next major version", replaceWith = kotlin.ReplaceWith(expression = "", imports = {})) public open fun stripLeading(): kotlin.String!
+    @kotlin.Deprecated(level = DeprecationLevel.WARNING, message = "This member is not fully supported by Kotlin compiler, so it may be absent or have different signature in next major version", replaceWith = kotlin.ReplaceWith(expression = "", imports = {})) public open fun stripTrailing(): kotlin.String!
     public open override /*1*/ fun subSequence(/*0*/ startIndex: kotlin.Int, /*1*/ endIndex: kotlin.Int): kotlin.CharSequence
 
     public companion object Companion {
diff --git a/compiler/testData/diagnostics/testWithModifiedMockJdk/newStringMethods.kt b/compiler/testData/diagnostics/testWithModifiedMockJdk/newStringMethods.kt
new file mode 100644
index 00000000000..53a19e64041
--- /dev/null
+++ b/compiler/testData/diagnostics/testWithModifiedMockJdk/newStringMethods.kt
@@ -0,0 +1,11 @@
+// !CHECK_TYPE
+// SKIP_TXT
+
+fun foo(s: String) {
+    s.isBlank()
+    s.lines().checkType { _<List<String>>() }
+    s.repeat(1)
+
+    // We don't have `strip` extension, so leave it for a while in gray list
+    s.<!DEPRECATION!>strip<!>()
+}
diff --git a/compiler/testData/mockJDKModified/rt.jar b/compiler/testData/mockJDKModified/rt.jar
index 64d380ad782..1241c3339a6 100644
Binary files a/compiler/testData/mockJDKModified/rt.jar and b/compiler/testData/mockJDKModified/rt.jar differ
diff --git a/compiler/tests-common/tests/org/jetbrains/kotlin/test/TestJdkKind.java b/compiler/tests-common/tests/org/jetbrains/kotlin/test/TestJdkKind.java
index e29fcd46cc1..35d3e901642 100644
--- a/compiler/tests-common/tests/org/jetbrains/kotlin/test/TestJdkKind.java
+++ b/compiler/tests-common/tests/org/jetbrains/kotlin/test/TestJdkKind.java
@@ -20,6 +20,7 @@ public enum TestJdkKind {
     MOCK_JDK,
     // Differs from common mock JDK only by one additional 'nonExistingMethod' in Collection and constructor from Double in Throwable
     // It's needed to test the way we load additional built-ins members that neither in black nor white lists
+    // Also, now it contains new methods in java.lang.String introduced in JDK 11
     MODIFIED_MOCK_JDK,
     // JDK found at $JDK_16
     FULL_JDK_6,
diff --git a/compiler/tests-java8/tests/org/jetbrains/kotlin/serialization/builtins/AdditionalBuiltInsMembersSignatureListsTest.kt b/compiler/tests-java8/tests/org/jetbrains/kotlin/serialization/builtins/AdditionalBuiltInsMembersSignatureListsTest.kt
index 718ff922fcf..63a566015c0 100644
--- a/compiler/tests-java8/tests/org/jetbrains/kotlin/serialization/builtins/AdditionalBuiltInsMembersSignatureListsTest.kt
+++ b/compiler/tests-java8/tests/org/jetbrains/kotlin/serialization/builtins/AdditionalBuiltInsMembersSignatureListsTest.kt
@@ -57,8 +57,13 @@ class AdditionalBuiltInsMembersSignatureListsTest : KotlinTestWithEnvironment()
 
             val scope = classDescriptor.unsubstitutedMemberScope
 
+            val lateJdkSignatures = LATE_JDK_SIGNATURES[internalName] ?: emptySet()
+
             jvmDescriptors.forEach {
                 jvmDescriptor ->
+
+                if (jvmDescriptor in lateJdkSignatures) return@forEach
+
                 val stringName = jvmDescriptor.split("(")[0]
                 val functions =
                         if (stringName == "<init>")
@@ -72,4 +77,8 @@ class AdditionalBuiltInsMembersSignatureListsTest : KotlinTestWithEnvironment()
             }
         }
     }
+
+    private val LATE_JDK_SIGNATURES = mapOf(
+        "java/lang/String" to setOf("isBlank()Z", "lines()Ljava/util/stream/Stream;", "repeat(I)Ljava/lang/String;")
+    )
 }
diff --git a/compiler/tests/org/jetbrains/kotlin/cfg/DiagnosticsWithModifiedMockJdkTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/cfg/DiagnosticsWithModifiedMockJdkTestGenerated.java
index 30d3f488b6a..37bb8ca0111 100644
--- a/compiler/tests/org/jetbrains/kotlin/cfg/DiagnosticsWithModifiedMockJdkTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/cfg/DiagnosticsWithModifiedMockJdkTestGenerated.java
@@ -29,6 +29,11 @@ public class DiagnosticsWithModifiedMockJdkTestGenerated extends AbstractDiagnos
         KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/diagnostics/testWithModifiedMockJdk"), Pattern.compile("^(.+)\\.kt$"), TargetBackend.ANY, true);
     }
 
+    @TestMetadata("newStringMethods.kt")
+    public void testNewStringMethods() throws Exception {
+        runTest("compiler/testData/diagnostics/testWithModifiedMockJdk/newStringMethods.kt");
+    }
+
     @TestMetadata("notConsideredMethod.kt")
     public void testNotConsideredMethod() throws Exception {
         runTest("compiler/testData/diagnostics/testWithModifiedMockJdk/notConsideredMethod.kt");
diff --git a/core/descriptors.jvm/src/org/jetbrains/kotlin/builtins/jvm/JvmBuiltInsSettings.kt b/core/descriptors.jvm/src/org/jetbrains/kotlin/builtins/jvm/JvmBuiltInsSettings.kt
index 7fb1f6537e0..4af1c60c296 100644
--- a/core/descriptors.jvm/src/org/jetbrains/kotlin/builtins/jvm/JvmBuiltInsSettings.kt
+++ b/core/descriptors.jvm/src/org/jetbrains/kotlin/builtins/jvm/JvmBuiltInsSettings.kt
@@ -371,7 +371,8 @@ open class JvmBuiltInsSettings(
                             "startsWith(Ljava/lang/String;I)Z", "startsWith(Ljava/lang/String;)Z", "substring(II)Ljava/lang/String;",
                             "substring(I)Ljava/lang/String;", "toCharArray()[C", "toLowerCase()Ljava/lang/String;",
                             "toLowerCase(Ljava/util/Locale;)Ljava/lang/String;", "toUpperCase()Ljava/lang/String;",
-                            "toUpperCase(Ljava/util/Locale;)Ljava/lang/String;", "trim()Ljava/lang/String;"
+                            "toUpperCase(Ljava/util/Locale;)Ljava/lang/String;", "trim()Ljava/lang/String;",
+                            "isBlank()Z", "lines()Ljava/util/stream/Stream;", "repeat(I)Ljava/lang/String;"
                         ) +
 
                         inJavaLang("Double", "isInfinite()Z", "isNaN()Z") +