diff --git a/skiko/src/commonMain/kotlin/org/jetbrains/skia/impl/Managed.kt b/skiko/src/commonMain/kotlin/org/jetbrains/skia/impl/Managed.kt
index c9d7130e8..de6b8641f 100644
--- a/skiko/src/commonMain/kotlin/org/jetbrains/skia/impl/Managed.kt
+++ b/skiko/src/commonMain/kotlin/org/jetbrains/skia/impl/Managed.kt
@@ -4,6 +4,8 @@ package org.jetbrains.skia.impl
  * Peer for a native object.
  */
 expect abstract class Managed(ptr: NativePointer, finalizer: NativePointer, managed: Boolean = true) : Native {
+    override val _ptr: NativePointer
+
     /**
      * Free underlying native resource, peer is useless afterwards.
      */
diff --git a/skiko/src/commonMain/kotlin/org/jetbrains/skia/impl/Native.kt b/skiko/src/commonMain/kotlin/org/jetbrains/skia/impl/Native.kt
index d43013e24..b2840e28c 100644
--- a/skiko/src/commonMain/kotlin/org/jetbrains/skia/impl/Native.kt
+++ b/skiko/src/commonMain/kotlin/org/jetbrains/skia/impl/Native.kt
@@ -6,8 +6,8 @@ expect class NativePointer
 
 expect class InteropPointer
 
-expect abstract class Native(ptr: NativePointer) {
-    internal var _ptr: NativePointer
+expect abstract class Native() {
+    internal abstract val _ptr: NativePointer
     internal open fun nativeEquals(other: Native?): Boolean
 
     companion object {
diff --git a/skiko/src/commonMain/kotlin/org/jetbrains/skia/paragraph/ParagraphCache.kt b/skiko/src/commonMain/kotlin/org/jetbrains/skia/paragraph/ParagraphCache.kt
index ef2f4a59e..2c6517405 100644
--- a/skiko/src/commonMain/kotlin/org/jetbrains/skia/paragraph/ParagraphCache.kt
+++ b/skiko/src/commonMain/kotlin/org/jetbrains/skia/paragraph/ParagraphCache.kt
@@ -8,13 +8,15 @@ import org.jetbrains.skia.ExternalSymbolName
 import org.jetbrains.skia.impl.NativePointer
 import org.jetbrains.skia.impl.getPtr
 
-class ParagraphCache internal constructor(owner: FontCollection, ptr: NativePointer) : Native(ptr) {
+class ParagraphCache internal constructor(owner: FontCollection, ptr: NativePointer) : Native() {
     companion object {
         init {
             staticLoad()
         }
     }
 
+    override val _ptr: NativePointer= ptr
+
     fun abandon() {
         try {
             _validate()
diff --git a/skiko/src/commonTest/kotlin/org/jetbrains/skia/DataTest.kt b/skiko/src/commonTest/kotlin/org/jetbrains/skia/DataTest.kt
index fabb13b0b..13b21bd1f 100644
--- a/skiko/src/commonTest/kotlin/org/jetbrains/skia/DataTest.kt
+++ b/skiko/src/commonTest/kotlin/org/jetbrains/skia/DataTest.kt
@@ -82,7 +82,7 @@ class DataTest {
             it
         }
 
-        assertEquals(NullPointer, copiedData._ptr)
+        assertTrue(copiedData.isClosed)
         assertEquals(originalDataPtr, originalData._ptr)
 
         assertContentEquals(
diff --git a/skiko/src/jsMain/kotlin/org/jetbrains/skia/impl/Managed.js.kt b/skiko/src/jsMain/kotlin/org/jetbrains/skia/impl/Managed.js.kt
index 9f28b3bfb..6985453d7 100644
--- a/skiko/src/jsMain/kotlin/org/jetbrains/skia/impl/Managed.js.kt
+++ b/skiko/src/jsMain/kotlin/org/jetbrains/skia/impl/Managed.js.kt
@@ -26,24 +26,36 @@ private fun unregister(managed: Managed) {
     registry.unregister(managed)
 }
 
-actual abstract class Managed actual constructor(ptr: NativePointer, finalizer: NativePointer, managed: Boolean) : Native(ptr) {
+actual abstract class Managed actual constructor(ptr: NativePointer, finalizer: NativePointer, managed: Boolean) : Native() {
     private var cleaner: FinalizationThunk? = null
 
+    private var __ptr: NativePointer = ptr.also {
+        require(it != NullPointer) {
+            "Can't wrap NullPointer"
+        }
+    }
+
+    actual override val _ptr: NativePointer get() = __ptr.also {
+        check(__ptr != NullPointer) {
+            "Object already closed: ${this::class.simpleName}"
+        }
+    }
+
     actual open fun close() {
-        if (NullPointer == _ptr)
-            throw RuntimeException("Object already closed: ${this::class.simpleName}, _ptr=$_ptr")
-        else if (null == cleaner)
-            throw RuntimeException("Object is not managed, can't close(): ${this::class.simpleName}, _ptr=$_ptr")
-        else {
-            unregister(this)
-            cleaner!!.clean()
-            cleaner = null
-            _ptr = 0
+        check(__ptr != NullPointer) {
+            "Object already closed: ${this::class.simpleName}"
+        }
+        check(null != cleaner) {
+            "Object is not managed, can't close(): ${this::class.simpleName}, _ptr=$__ptr"
         }
+        unregister(this)
+        cleaner!!.clean()
+        cleaner = null
+        __ptr = 0
     }
 
     actual open val isClosed: Boolean
-        get() = _ptr == NullPointer
+        get() = __ptr == NullPointer
 
     init {
         if (managed) {
diff --git a/skiko/src/jsMain/kotlin/org/jetbrains/skia/impl/Native.js.kt b/skiko/src/jsMain/kotlin/org/jetbrains/skia/impl/Native.js.kt
index 5cda71faf..0fce332ea 100644
--- a/skiko/src/jsMain/kotlin/org/jetbrains/skia/impl/Native.js.kt
+++ b/skiko/src/jsMain/kotlin/org/jetbrains/skia/impl/Native.js.kt
@@ -2,8 +2,8 @@ package org.jetbrains.skia.impl
 
 import org.khronos.webgl.ArrayBufferView
 
-actual abstract class Native actual constructor(ptr: NativePointer) {
-    actual var _ptr: NativePointer
+actual abstract class Native {
+    actual abstract val _ptr: NativePointer
 
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
@@ -26,11 +26,6 @@ actual abstract class Native actual constructor(ptr: NativePointer) {
     actual override fun toString(): String {
         return this::class.simpleName + "(_ptr=0x" + _ptr.toString(16) + ")"
     }
-
-    init {
-        if (ptr == NullPointer) throw RuntimeException("Can't wrap nullptr")
-        _ptr = ptr
-    }
 }
 
 internal actual fun reachabilityBarrier(obj: Any?) {}
diff --git a/skiko/src/jvmMain/cpp/common/interop.cc b/skiko/src/jvmMain/cpp/common/interop.cc
index 8ec5be460..665851865 100644
--- a/skiko/src/jvmMain/cpp/common/interop.cc
+++ b/skiko/src/jvmMain/cpp/common/interop.cc
@@ -896,16 +896,16 @@ namespace skija {
 
     namespace impl {
         namespace Native {
-            jfieldID _ptr;
+            jmethodID _ptr;
 
             void onLoad(JNIEnv* env) {
                 jclass cls = env->FindClass("org/jetbrains/skia/impl/Native");
-                _ptr = env->GetFieldID(cls, "_ptr", "J");
+                _ptr = env->GetMethodID(cls, "getPtr", "()J");
             }
 
             void* fromJava(JNIEnv* env, jobject obj, jclass cls) {
                 if (env->IsInstanceOf(obj, cls)) {
-                    jlong ptr = env->GetLongField(obj, skija::impl::Native::_ptr);
+                    jlong ptr = env->CallLongMethod(obj, skija::impl::Native::_ptr);
                     return reinterpret_cast<void*>(static_cast<uintptr_t>(ptr));
                 }
                 return nullptr;
diff --git a/skiko/src/jvmMain/cpp/common/interop.hh b/skiko/src/jvmMain/cpp/common/interop.hh
index 80ae5bd80..39d4b17f6 100644
--- a/skiko/src/jvmMain/cpp/common/interop.hh
+++ b/skiko/src/jvmMain/cpp/common/interop.hh
@@ -329,7 +329,7 @@ namespace skija {
 
     namespace impl {
         namespace Native {
-            extern jfieldID _ptr;
+            extern jmethodID _ptr;
             void onLoad(JNIEnv* env);
             void onUnload(JNIEnv* env);
             void* fromJava(JNIEnv* env, jobject obj, jclass cls);
diff --git a/skiko/src/jvmMain/kotlin/org/jetbrains/skia/impl/Managed.jvm.kt b/skiko/src/jvmMain/kotlin/org/jetbrains/skia/impl/Managed.jvm.kt
index 2179e8ab8..d69ae7759 100644
--- a/skiko/src/jvmMain/kotlin/org/jetbrains/skia/impl/Managed.jvm.kt
+++ b/skiko/src/jvmMain/kotlin/org/jetbrains/skia/impl/Managed.jvm.kt
@@ -8,22 +8,33 @@ import kotlin.concurrent.thread
 // Consider using this on all JVM platforms eventually.
 actual abstract class Managed actual constructor(
     ptr: Long, finalizer: Long, managed: Boolean
-) : Native(ptr), AutoCloseable {
+) : Native(), AutoCloseable {
+    private var __ptr: NativePointer = ptr.also {
+        require(it != NullPointer) {
+            "Can't wrap NullPointer"
+        }
+    }
+
+    actual override val _ptr: NativePointer get() = __ptr.also {
+        check(__ptr != NullPointer) {
+            "Object already closed: $javaClass"
+        }
+    }
 
     actual override fun close() {
-        if (0L == _ptr)
-            throw RuntimeException("Object already closed: $javaClass, _ptr=$_ptr")
-        else if (null == cleanable)
-            throw RuntimeException("Object is not managed in JVM, can't close(): $javaClass, _ptr=$_ptr")
-        else {
-            cleanable!!.clean()
-            cleanable = null
-            _ptr = 0
+        check(__ptr != NullPointer) {
+            "Object already closed: $javaClass"
+        }
+        check(null != cleanable) {
+            "Object is not managed in JVM, can't close(): $javaClass, _ptr=$__ptr"
         }
+        cleanable!!.clean()
+        cleanable = null
+        __ptr = 0
     }
 
     actual open val isClosed: Boolean
-        get() = _ptr == 0L
+        get() = __ptr == 0L
 
     class CleanerThunk(var className: String, var ptr: Long, var finalizerPtr: Long) : Runnable {
         override fun run() {
diff --git a/skiko/src/jvmMain/kotlin/org/jetbrains/skia/impl/Native.jvm.kt b/skiko/src/jvmMain/kotlin/org/jetbrains/skia/impl/Native.jvm.kt
index 6552b4f2b..dcccc81fa 100644
--- a/skiko/src/jvmMain/kotlin/org/jetbrains/skia/impl/Native.jvm.kt
+++ b/skiko/src/jvmMain/kotlin/org/jetbrains/skia/impl/Native.jvm.kt
@@ -2,8 +2,10 @@ package org.jetbrains.skia.impl
 
 import java.lang.ref.Reference
 
-actual abstract class Native actual constructor(ptr: NativePointer) {
-    internal actual var _ptr: NativePointer
+actual abstract class Native {
+    internal actual abstract val _ptr: NativePointer
+
+    fun getPtr() = _ptr
 
     actual companion object {
         actual val NullPointer: NativePointer
@@ -35,11 +37,6 @@ actual abstract class Native actual constructor(ptr: NativePointer) {
     internal actual open fun nativeEquals(other: Native?): Boolean {
         return false
     }
-
-    init {
-        if (ptr == NullPointer) throw RuntimeException("Can't wrap nullptr")
-        _ptr = ptr
-    }
 }
 
 internal actual fun reachabilityBarrier(obj: Any?) {
diff --git a/skiko/src/nativeMain/kotlin/org/jetbrains/skia/impl/Managed.native.kt b/skiko/src/nativeMain/kotlin/org/jetbrains/skia/impl/Managed.native.kt
index de33efd09..7a4ed394f 100644
--- a/skiko/src/nativeMain/kotlin/org/jetbrains/skia/impl/Managed.native.kt
+++ b/skiko/src/nativeMain/kotlin/org/jetbrains/skia/impl/Managed.native.kt
@@ -22,7 +22,7 @@ private class FinalizationThunk(private val finalizer: NativePointer, val classN
 }
 
 actual abstract class Managed actual constructor(
-        ptr: NativePointer, finalizer: NativePointer, managed: Boolean) : Native(ptr) {
+        ptr: NativePointer, finalizer: NativePointer, managed: Boolean) : Native() {
 
     private val thunk: FinalizationThunk? = if (managed) {
         require(ptr != NullPointer) { "Managed ptr is nullptr" }
@@ -39,23 +39,35 @@ actual abstract class Managed actual constructor(
         }
     } else null
 
+    private var __ptr: NativePointer = ptr.also {
+        require(it != NullPointer) {
+            "Can't wrap NullPointer"
+        }
+    }
+
+    actual override val _ptr: NativePointer get() = __ptr.also {
+        check(__ptr != NullPointer) {
+            "Object already closed: ${this::class.simpleName}"
+        }
+    }
+
     actual open fun close() {
-        require(_ptr != NullPointer) {
-            "Object already closed: ${this::class.simpleName}, _ptr=$_ptr"
+        check(__ptr != NullPointer) {
+            "Object already closed: ${this::class.simpleName}"
         }
-        requireNotNull(thunk) {
-            "Object is not managed in K/N runtime, can't close(): ${this::class.simpleName}, _ptr=$_ptr"
+        checkNotNull(thunk) {
+            "Object is not managed in K/N runtime, can't close(): ${this::class.simpleName}, _ptr=$__ptr"
         }
-        require(thunk.isActive) {
-            "Object is closed already, can't close(): ${this::class.simpleName}, _ptr=$_ptr"
+        check(thunk.isActive) {
+            "Object is closed already, can't close(): ${this::class.simpleName}, _ptr=$__ptr"
         }
 
         thunk.clean()
-        _ptr = NullPointer
+        __ptr = NullPointer
     }
 
     actual open val isClosed: Boolean
-        get() = _ptr == NullPointer
+        get() = __ptr == NullPointer
 }
 
 @ExternalSymbolName("org_jetbrains_skia_impl_Managed__invokeFinalizer")
diff --git a/skiko/src/nativeMain/kotlin/org/jetbrains/skia/impl/Native.native.kt b/skiko/src/nativeMain/kotlin/org/jetbrains/skia/impl/Native.native.kt
index 859061532..5a38151e5 100644
--- a/skiko/src/nativeMain/kotlin/org/jetbrains/skia/impl/Native.native.kt
+++ b/skiko/src/nativeMain/kotlin/org/jetbrains/skia/impl/Native.native.kt
@@ -4,8 +4,8 @@ import kotlinx.cinterop.*
 import org.jetbrains.skia.ExternalSymbolName
 import kotlin.native.internal.NativePtr
 
-actual abstract class Native actual constructor(ptr: NativePointer) {
-    internal actual var _ptr: NativePointer
+actual abstract class Native {
+    internal actual open val _ptr: NativePointer
 
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
@@ -40,11 +40,6 @@ actual abstract class Native actual constructor(ptr: NativePointer) {
     actual override fun toString(): String {
         return this::class.simpleName + "(_ptr=0x" + _ptr.toString() + ")"
     }
-
-    init {
-        if (ptr == NativePtr.NULL) throw RuntimeException("Can't wrap nullptr")
-        _ptr = ptr
-    }
 }
 
 actual typealias NativePointer = NativePtr