Method can be hidden if it is annotated with kotlin.internal.PlatformDependent,

or is a Java method from a Kotlin built-in class (transitively).

https://github.com/Kotlin/KEEP/blob/master/proposals/jdk-dependent-built-ins.md#backward-compatibility-of-overrides

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/JvmOverridesBackwardCompatibilityHelper.kt

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2010-2016 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.kotlin.resolve.jvm
+
+import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
+import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.load.java.descriptors.JavaMethodDescriptor
+import org.jetbrains.kotlin.platform.JavaToKotlinClassMap
+import org.jetbrains.kotlin.resolve.DescriptorUtils
+import org.jetbrains.kotlin.resolve.OverridesBackwardCompatibilityHelper
+import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameUnsafe
+import org.jetbrains.kotlin.serialization.deserialization.PLATFORM_DEPENDENT_ANNOTATION_FQ_NAME
+
+object JvmOverridesBackwardCompatibilityHelper : OverridesBackwardCompatibilityHelper {
+    override fun overrideCanBeOmitted(overridingDescriptor: CallableMemberDescriptor): Boolean {
+        val visitedDescriptors = hashSetOf<CallableMemberDescriptor>()
+        return overridingDescriptor.overriddenDescriptors.all {
+            isPlatformSpecificDescriptorThatCanBeImplicitlyOverridden(it, visitedDescriptors)
+        }
+    }
+
+    private fun isPlatformSpecificDescriptorThatCanBeImplicitlyOverridden(
+            overriddenDescriptor: CallableMemberDescriptor,
+            visitedDescriptors: MutableSet<CallableMemberDescriptor>
+    ): Boolean {
+        if (overriddenDescriptor.modality == Modality.FINAL) return false
+
+        if (visitedDescriptors.contains(overriddenDescriptor.original)) return true
+        visitedDescriptors.add(overriddenDescriptor.original)
+
+        when (overriddenDescriptor.kind) {
+            CallableMemberDescriptor.Kind.DELEGATION,
+            CallableMemberDescriptor.Kind.FAKE_OVERRIDE ->
+                return isOverridingOnlyDescriptorsThatCanBeImplicitlyOverridden(overriddenDescriptor, visitedDescriptors)
+
+            CallableMemberDescriptor.Kind.DECLARATION -> {
+                when {
+                    overriddenDescriptor.annotations.hasAnnotation(PLATFORM_DEPENDENT_ANNOTATION_FQ_NAME) ->
+                        return true
+                    overriddenDescriptor is JavaMethodDescriptor -> {
+                        val containingClass = DescriptorUtils.getContainingClass(overriddenDescriptor)
+                                              ?: return false
+
+                        if (JavaToKotlinClassMap.INSTANCE.mapKotlinToJava(containingClass.fqNameUnsafe) != null) return true
+                        if (overriddenDescriptor.overriddenDescriptors.isEmpty()) return false
+
+                        return isOverridingOnlyDescriptorsThatCanBeImplicitlyOverridden(overriddenDescriptor, visitedDescriptors)
+                    }
+                    else ->
+                        return false
+                }
+
+            }
+
+            else ->
+                return false
+        }
+    }
+
+    private fun isOverridingOnlyDescriptorsThatCanBeImplicitlyOverridden(
+            overriddenDescriptor: CallableMemberDescriptor,
+            visitedDescriptors: MutableSet<CallableMemberDescriptor>
+    ): Boolean =
+            overriddenDescriptor.overriddenDescriptors.all {
+                isPlatformSpecificDescriptorThatCanBeImplicitlyOverridden(it, visitedDescriptors)
+            }
+
+}

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/platform/JvmPlatformConfigurator.kt

@@ -24,10 +24,7 @@ import org.jetbrains.kotlin.resolve.PlatformConfigurator
 import org.jetbrains.kotlin.resolve.calls.checkers.ReifiedTypeParameterSubstitutionChecker
 import org.jetbrains.kotlin.resolve.checkers.MissingDependencyClassChecker
 import org.jetbrains.kotlin.resolve.checkers.HeaderImplDeclarationChecker
-import org.jetbrains.kotlin.resolve.jvm.JvmDelegationFilter
-import org.jetbrains.kotlin.resolve.jvm.JvmOverloadFilter
-import org.jetbrains.kotlin.resolve.jvm.JvmTypeSpecificityComparator
-import org.jetbrains.kotlin.resolve.jvm.RuntimeAssertionsTypeChecker
+import org.jetbrains.kotlin.resolve.jvm.*
 import org.jetbrains.kotlin.resolve.jvm.checkers.*
 import org.jetbrains.kotlin.resolve.lazy.DelegationFilter
 import org.jetbrains.kotlin.synthetic.JavaSyntheticConstructorsProvider
@@ -86,7 +83,9 @@ object JvmPlatformConfigurator : PlatformConfigurator(
 
         platformToKotlinClassMap = JavaToKotlinClassMap.INSTANCE,
 
-        delegationFilter = JvmDelegationFilter
+        delegationFilter = JvmDelegationFilter,
+
+        overridesBackwardCompatibilityHelper = JvmOverridesBackwardCompatibilityHelper
 ) {
     override fun configureModuleComponents(container: StorageComponentContainer) {
         container.useImpl<JvmReflectionAPICallChecker>()