diff --git a/src/main/java/org/apache/datasketches/kll/KllDoublesSketch.java b/src/main/java/org/apache/datasketches/kll/KllDoublesSketch.java
index b51624988..6ef6a172e 100644
--- a/src/main/java/org/apache/datasketches/kll/KllDoublesSketch.java
+++ b/src/main/java/org/apache/datasketches/kll/KllDoublesSketch.java
@@ -21,8 +21,9 @@
 
 import static java.lang.Math.max;
 import static java.lang.Math.min;
+import static org.apache.datasketches.kll.KllPreambleUtil.getMemoryUpdatableFormatFlag;
+import static org.apache.datasketches.kll.KllSketch.Error.MUST_NOT_BE_UPDATABLE_FORMAT;
 import static org.apache.datasketches.kll.KllSketch.Error.MUST_NOT_CALL;
-import static org.apache.datasketches.kll.KllSketch.Error.SRC_MUST_BE_DOUBLE;
 import static org.apache.datasketches.kll.KllSketch.Error.TGT_IS_READ_ONLY;
 import static org.apache.datasketches.kll.KllSketch.Error.kllSketchThrow;
 
@@ -58,9 +59,8 @@ public static int getMaxSerializedSizeBytes(final int k, final long n, final boo
    */
   public static KllDoublesSketch heapify(final Memory srcMem) {
     Objects.requireNonNull(srcMem, "Parameter 'srcMem' must not be null");
-    final KllMemoryValidate memVal = new KllMemoryValidate(srcMem);
-    if (!memVal.doublesSketch) { Error.kllSketchThrow(SRC_MUST_BE_DOUBLE); }
-    return new KllHeapDoublesSketch(srcMem, memVal);
+    if (getMemoryUpdatableFormatFlag(srcMem)) { Error.kllSketchThrow(MUST_NOT_BE_UPDATABLE_FORMAT); }
+    return KllHeapDoublesSketch.heapifyImpl(srcMem);
   }
 
   /**
diff --git a/src/main/java/org/apache/datasketches/kll/KllFloatsSketch.java b/src/main/java/org/apache/datasketches/kll/KllFloatsSketch.java
index 17275d42f..7f0b0f10c 100644
--- a/src/main/java/org/apache/datasketches/kll/KllFloatsSketch.java
+++ b/src/main/java/org/apache/datasketches/kll/KllFloatsSketch.java
@@ -21,8 +21,9 @@
 
 import static java.lang.Math.max;
 import static java.lang.Math.min;
+import static org.apache.datasketches.kll.KllPreambleUtil.getMemoryUpdatableFormatFlag;
+import static org.apache.datasketches.kll.KllSketch.Error.MUST_NOT_BE_UPDATABLE_FORMAT;
 import static org.apache.datasketches.kll.KllSketch.Error.MUST_NOT_CALL;
-import static org.apache.datasketches.kll.KllSketch.Error.SRC_MUST_BE_FLOAT;
 import static org.apache.datasketches.kll.KllSketch.Error.TGT_IS_READ_ONLY;
 import static org.apache.datasketches.kll.KllSketch.Error.kllSketchThrow;
 
@@ -58,9 +59,8 @@ public static int getMaxSerializedSizeBytes(final int k, final long n, final boo
    */
   public static KllFloatsSketch heapify(final Memory srcMem) {
     Objects.requireNonNull(srcMem, "Parameter 'srcMem' must not be null");
-    final KllMemoryValidate memVal = new KllMemoryValidate(srcMem);
-    if (memVal.doublesSketch) { Error.kllSketchThrow(SRC_MUST_BE_FLOAT); }
-    return new KllHeapFloatsSketch(srcMem, memVal);
+    if (getMemoryUpdatableFormatFlag(srcMem)) { Error.kllSketchThrow(MUST_NOT_BE_UPDATABLE_FORMAT); }
+    return KllHeapFloatsSketch.heapifyImpl(srcMem);
   }
 
   /**
diff --git a/src/main/java/org/apache/datasketches/kll/KllHeapDoublesSketch.java b/src/main/java/org/apache/datasketches/kll/KllHeapDoublesSketch.java
index 7383ddf38..189b95606 100644
--- a/src/main/java/org/apache/datasketches/kll/KllHeapDoublesSketch.java
+++ b/src/main/java/org/apache/datasketches/kll/KllHeapDoublesSketch.java
@@ -23,8 +23,11 @@
 import static org.apache.datasketches.kll.KllPreambleUtil.DATA_START_ADR_SINGLE_ITEM;
 import static org.apache.datasketches.kll.KllSketch.Error.MUST_NOT_CALL;
 import static org.apache.datasketches.kll.KllSketch.Error.NOT_SINGLE_ITEM;
+import static org.apache.datasketches.kll.KllSketch.Error.SRC_MUST_BE_DOUBLE;
 import static org.apache.datasketches.kll.KllSketch.Error.kllSketchThrow;
 
+import java.util.Objects;
+
 import org.apache.datasketches.memory.Memory;
 
 /**
@@ -74,9 +77,9 @@ final class KllHeapDoublesSketch extends KllDoublesSketch {
   /**
    * Heapify constructor.
    * @param srcMem Memory object that contains data serialized by this sketch.
-   * @param memVal the MemoryCheck object
+   * @param memVal the MemoryVaidate object
    */
-  KllHeapDoublesSketch(final Memory srcMem, final KllMemoryValidate memVal) {
+  private KllHeapDoublesSketch(final Memory srcMem, final KllMemoryValidate memVal) {
     super(null, null );
     k_ = memVal.k;
     m_ = memVal.m;
@@ -117,6 +120,13 @@ else if (memVal.singleItem && !updatableMemFormat) {
     }
   }
 
+  static KllHeapDoublesSketch heapifyImpl(final Memory srcMem) {
+    Objects.requireNonNull(srcMem, "Parameter 'srcMem' must not be null");
+    final KllMemoryValidate memVal = new KllMemoryValidate(srcMem);
+    if (!memVal.doublesSketch) { Error.kllSketchThrow(SRC_MUST_BE_DOUBLE); }
+    return new KllHeapDoublesSketch(srcMem, memVal);
+  }
+
   @Override
   public int getK() { return k_; }
 
diff --git a/src/main/java/org/apache/datasketches/kll/KllHeapFloatsSketch.java b/src/main/java/org/apache/datasketches/kll/KllHeapFloatsSketch.java
index 32c331bd5..3499850e6 100644
--- a/src/main/java/org/apache/datasketches/kll/KllHeapFloatsSketch.java
+++ b/src/main/java/org/apache/datasketches/kll/KllHeapFloatsSketch.java
@@ -23,8 +23,11 @@
 import static org.apache.datasketches.kll.KllPreambleUtil.DATA_START_ADR_SINGLE_ITEM;
 import static org.apache.datasketches.kll.KllSketch.Error.MUST_NOT_CALL;
 import static org.apache.datasketches.kll.KllSketch.Error.NOT_SINGLE_ITEM;
+import static org.apache.datasketches.kll.KllSketch.Error.SRC_MUST_BE_FLOAT;
 import static org.apache.datasketches.kll.KllSketch.Error.kllSketchThrow;
 
+import java.util.Objects;
+
 import org.apache.datasketches.memory.Memory;
 
 /**
@@ -74,9 +77,9 @@ final class KllHeapFloatsSketch extends KllFloatsSketch {
   /**
    * Heapify constructor.
    * @param srcMem Memory object that contains data serialized by this sketch.
-   * @param memVal the MemoryCheck object
+   * @param memVal the MemoryValidate object
    */
-  KllHeapFloatsSketch(final Memory srcMem, final KllMemoryValidate memVal) {
+  private KllHeapFloatsSketch(final Memory srcMem, final KllMemoryValidate memVal) {
     super(null, null);
     k_ = memVal.k;
     m_ = memVal.m;
@@ -117,6 +120,13 @@ else if (memVal.singleItem && !updatableMemFormat) {
     }
   }
 
+  static KllHeapFloatsSketch heapifyImpl(final Memory srcMem) {
+    Objects.requireNonNull(srcMem, "Parameter 'srcMem' must not be null");
+    final KllMemoryValidate memVal = new KllMemoryValidate(srcMem);
+    if (memVal.doublesSketch) { Error.kllSketchThrow(SRC_MUST_BE_FLOAT); }
+    return new KllHeapFloatsSketch(srcMem, memVal);
+  }
+
   @Override
   public int getK() { return k_; }
 
diff --git a/src/main/java/org/apache/datasketches/kll/KllSketch.java b/src/main/java/org/apache/datasketches/kll/KllSketch.java
index e71623488..896cb1b9d 100644
--- a/src/main/java/org/apache/datasketches/kll/KllSketch.java
+++ b/src/main/java/org/apache/datasketches/kll/KllSketch.java
@@ -67,7 +67,7 @@
  *
  * @author Lee Rhodes, Kevin Lang
  */
-abstract class KllSketch {
+public abstract class KllSketch {
 
   /**
    * Used to define the variable type of the current instance of this class.
@@ -81,7 +81,8 @@ enum Error {
     MUST_NOT_CALL("This is an artifact of inheritance and should never be called."),
     SINGLE_ITEM_IMPROPER_CALL("Improper method use for single-item sketch"),
     MRS_MUST_NOT_BE_NULL("MemoryRequestServer cannot be null."),
-    NOT_SINGLE_ITEM("Sketch is not single item.");
+    NOT_SINGLE_ITEM("Sketch is not single item."),
+    MUST_NOT_BE_UPDATABLE_FORMAT("Given Memory object must not be in updatableFormat.");
 
     private String msg;
 
diff --git a/src/main/java/org/apache/datasketches/kll/package-info.java b/src/main/java/org/apache/datasketches/kll/package-info.java
index e42e6cb7c..87c410c3a 100644
--- a/src/main/java/org/apache/datasketches/kll/package-info.java
+++ b/src/main/java/org/apache/datasketches/kll/package-info.java
@@ -148,21 +148,8 @@
  * <li>Then <i>v<sub>lo</sub> &le; v &le; v<sub>hi</sub></i>, with 99% confidence.</li>
  * </ul>
  *
- * <p>The current implementations of the KLL sketch in the DataSketches Java library component include:</p>
- *
- * <ul>
- * <li><b>KllFloatsSketch</b>: This operates on the Java heap and uses the java <i>float</i> primitive for the
- * smallest possible size. It can be serialized to a compact, immutable format or to an updatable format, which can
- * be modified off-heap. </li>
- * <li><b>KllDoublesSketch</b>: This operates on the Java heap and uses the java <i>double</i> primitive for a much
- * larger range of numeric values, and is larger as a result. It can be serialized to a compact, immutable format or
- * to an updatable format, which can be modified off-heap.</li>
- * <li><b>KllFloatsSketchIterator</b>: Iterates over the retained values and weights of the KllFloatsSketch.</li>
- * <li><b>KllDoublesSketchIterator</b>: : Iterates over the retained values and weights of the KllDoublesSketch.</li>
- * </ul>
- *
- * <p>Please visit our website: <a href="https://datasketches.apache.org">DataSketches Home Page</a> for more
- * information.</p>
+ * <p>Please visit our website: <a href="https://datasketches.apache.org">DataSketches Home Page</a> and
+ * the Javadocs for more information.</p>
  *
  * @author Kevin Lang
  * @author Alexander Saydakov
diff --git a/src/test/java/org/apache/datasketches/kll/KllDirectDoublesSketchTest.java b/src/test/java/org/apache/datasketches/kll/KllDirectDoublesSketchTest.java
index 599368d6b..d43751e01 100644
--- a/src/test/java/org/apache/datasketches/kll/KllDirectDoublesSketchTest.java
+++ b/src/test/java/org/apache/datasketches/kll/KllDirectDoublesSketchTest.java
@@ -550,7 +550,7 @@ public void checkGetWritableMemory() {
     assertFalse(sketch.isFloatsSketch());
 
     final WritableMemory wmem = sketch.getWritableMemory();
-    final KllDoublesSketch sk = KllDoublesSketch.heapify(wmem);
+    final KllDoublesSketch sk = KllHeapDoublesSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), 200);
     assertEquals(sk.getN(), 200);
     assertFalse(sk.isEmpty());
@@ -584,7 +584,7 @@ public void checkHeapify() {
     WritableMemory dstMem = WritableMemory.allocate(6000);
     KllDoublesSketch sk = KllDoublesSketch.newDirectInstance(20, dstMem, memReqSvr);
     for (int i = 1; i <= 100; i++) { sk.update(i); }
-    KllDoublesSketch sk2 = KllDoublesSketch.heapify(dstMem);
+    KllDoublesSketch sk2 = KllHeapDoublesSketch.heapifyImpl(dstMem);
     assertEquals(sk2.getMinValue(), 1.0);
     assertEquals(sk2.getMaxValue(), 100.0);
   }
diff --git a/src/test/java/org/apache/datasketches/kll/KllDirectFloatsSketchTest.java b/src/test/java/org/apache/datasketches/kll/KllDirectFloatsSketchTest.java
index 2e202f3aa..a159dc545 100644
--- a/src/test/java/org/apache/datasketches/kll/KllDirectFloatsSketchTest.java
+++ b/src/test/java/org/apache/datasketches/kll/KllDirectFloatsSketchTest.java
@@ -550,7 +550,7 @@ public void checkGetWritableMemory() {
     assertFalse(sketch.isDoublesSketch());
 
     final WritableMemory wmem = sketch.getWritableMemory();
-    final KllFloatsSketch sk = KllFloatsSketch.heapify(wmem);
+    final KllFloatsSketch sk = KllHeapFloatsSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), 200);
     assertEquals(sk.getN(), 200);
     assertFalse(sk.isEmpty());
@@ -584,7 +584,7 @@ public void checkHeapify() {
     WritableMemory dstMem = WritableMemory.allocate(6000);
     KllFloatsSketch sk = KllFloatsSketch.newDirectInstance(20, dstMem, memReqSvr);
     for (int i = 1; i <= 100; i++) { sk.update(i); }
-    KllFloatsSketch sk2 = KllFloatsSketch.heapify(dstMem);
+    KllFloatsSketch sk2 = KllHeapFloatsSketch.heapifyImpl(dstMem);
     assertEquals(sk2.getMinValue(), 1.0);
     assertEquals(sk2.getMaxValue(), 100.0);
   }
diff --git a/src/test/java/org/apache/datasketches/kll/MiscDirectDoublesTest.java b/src/test/java/org/apache/datasketches/kll/MiscDirectDoublesTest.java
index 15337ad7a..84f5f37b2 100644
--- a/src/test/java/org/apache/datasketches/kll/MiscDirectDoublesTest.java
+++ b/src/test/java/org/apache/datasketches/kll/MiscDirectDoublesTest.java
@@ -245,7 +245,7 @@ public void checkSketchInitializeDoubleHeapifyUpdatableMem() {
     //println(sk2.toString(true, true));
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
-    sk = KllDoublesSketch.heapify(wmem);
+    sk = KllHeapDoublesSketch.heapifyImpl(wmem);
     println(sk.toString(true, true));
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), k + 1);
@@ -266,7 +266,7 @@ public void checkSketchInitializeDoubleHeapifyUpdatableMem() {
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
     //println(KllPreambleUtil.toString(wmem));
-    sk = KllDoublesSketch.heapify(wmem);
+    sk = KllHeapDoublesSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), 0);
     assertEquals(sk.getNumRetained(), 0);
@@ -287,7 +287,7 @@ public void checkSketchInitializeDoubleHeapifyUpdatableMem() {
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
     //println(KllPreambleUtil.memoryToString(wmem, true));
-    sk = KllDoublesSketch.heapify(wmem);
+    sk = KllHeapDoublesSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), 1);
     assertEquals(sk.getNumRetained(), 1);
diff --git a/src/test/java/org/apache/datasketches/kll/MiscDirectFloatsTest.java b/src/test/java/org/apache/datasketches/kll/MiscDirectFloatsTest.java
index b8a9aadc2..6810dc2dd 100644
--- a/src/test/java/org/apache/datasketches/kll/MiscDirectFloatsTest.java
+++ b/src/test/java/org/apache/datasketches/kll/MiscDirectFloatsTest.java
@@ -246,7 +246,7 @@ public void checkSketchInitializeFloatHeapifyUpdatableMem() {
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
     //println(KllPreambleUtil.toString(wmem));
-    sk = KllFloatsSketch.heapify(wmem);
+    sk = KllHeapFloatsSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), k + 1);
     assertEquals(sk.getNumRetained(), 11);
@@ -266,7 +266,7 @@ public void checkSketchInitializeFloatHeapifyUpdatableMem() {
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
     //println(KllPreambleUtil.toString(wmem));
-    sk = KllFloatsSketch.heapify(wmem);
+    sk = KllHeapFloatsSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), 0);
     assertEquals(sk.getNumRetained(), 0);
@@ -287,7 +287,7 @@ public void checkSketchInitializeFloatHeapifyUpdatableMem() {
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
     //println(KllPreambleUtil.toString(wmem));
-    sk = KllFloatsSketch.heapify(wmem);
+    sk = KllHeapFloatsSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), 1);
     assertEquals(sk.getNumRetained(), 1);
diff --git a/src/test/java/org/apache/datasketches/kll/MiscDoublesTest.java b/src/test/java/org/apache/datasketches/kll/MiscDoublesTest.java
index d2711411f..e86488aab 100644
--- a/src/test/java/org/apache/datasketches/kll/MiscDoublesTest.java
+++ b/src/test/java/org/apache/datasketches/kll/MiscDoublesTest.java
@@ -305,7 +305,7 @@ public void checkSketchInitializeDoubleHeapifyUpdatableMem() {
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
     println(KllPreambleUtil.toString(wmem, true));
-    sk = KllDoublesSketch.heapify(wmem);
+    sk = KllHeapDoublesSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), k + 1);
     assertEquals(sk.getNumRetained(), 11);
@@ -325,7 +325,7 @@ public void checkSketchInitializeDoubleHeapifyUpdatableMem() {
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
     println(KllPreambleUtil.toString(wmem, true));
-    sk = KllDoublesSketch.heapify(wmem);
+    sk = KllHeapDoublesSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), 0);
     assertEquals(sk.getNumRetained(), 0);
@@ -346,7 +346,7 @@ public void checkSketchInitializeDoubleHeapifyUpdatableMem() {
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
     println(KllPreambleUtil.toString(wmem, true));
-    sk = KllDoublesSketch.heapify(wmem);
+    sk = KllHeapDoublesSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), 1);
     assertEquals(sk.getNumRetained(), 1);
@@ -437,7 +437,7 @@ public void checkMemoryToStringDoubleUpdatable() {
     s = KllPreambleUtil.toString(wmem, true);
     println("step 1: sketch to byte[]/memory & analyze memory");
     println(s);
-    sk2 = KllDoublesSketch.heapify(wmem);
+    sk2 = KllHeapDoublesSketch.heapifyImpl(wmem);
     upBytes2 = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(upBytes2);
     s = KllPreambleUtil.toString(wmem, true);
@@ -455,7 +455,7 @@ public void checkMemoryToStringDoubleUpdatable() {
     s = KllPreambleUtil.toString(wmem, true);
     println("step 1: sketch to byte[]/memory & analyze memory");
     println(s);
-    sk2 = KllDoublesSketch.heapify(wmem);
+    sk2 = KllHeapDoublesSketch.heapifyImpl(wmem);
     upBytes2 = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(upBytes2);
     s = KllPreambleUtil.toString(wmem, true);
@@ -471,7 +471,7 @@ public void checkMemoryToStringDoubleUpdatable() {
     s = KllPreambleUtil.toString(wmem, true);
     println("step 1: sketch to byte[]/memory & analyze memory");
     println(s);
-    sk2 = KllDoublesSketch.heapify(wmem);
+    sk2 = KllHeapDoublesSketch.heapifyImpl(wmem);
     upBytes2 = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(upBytes2);
     s = KllPreambleUtil.toString(wmem, true);
diff --git a/src/test/java/org/apache/datasketches/kll/MiscFloatsTest.java b/src/test/java/org/apache/datasketches/kll/MiscFloatsTest.java
index 406e98c37..57cc244a0 100644
--- a/src/test/java/org/apache/datasketches/kll/MiscFloatsTest.java
+++ b/src/test/java/org/apache/datasketches/kll/MiscFloatsTest.java
@@ -305,7 +305,7 @@ public void checkSketchInitializeFloatHeapifyUpdatableMem() {
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
     println(KllPreambleUtil.toString(wmem, true));
-    sk = KllFloatsSketch.heapify(wmem);
+    sk = KllHeapFloatsSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), k + 1);
     assertEquals(sk.getNumRetained(), 11);
@@ -325,7 +325,7 @@ public void checkSketchInitializeFloatHeapifyUpdatableMem() {
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
     println(KllPreambleUtil.toString(wmem, true));
-    sk = KllFloatsSketch.heapify(wmem);
+    sk = KllHeapFloatsSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), 0);
     assertEquals(sk.getNumRetained(), 0);
@@ -346,7 +346,7 @@ public void checkSketchInitializeFloatHeapifyUpdatableMem() {
     compBytes = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(compBytes);
     println(KllPreambleUtil.toString(wmem, true));
-    sk = KllFloatsSketch.heapify(wmem);
+    sk = KllHeapFloatsSketch.heapifyImpl(wmem);
     assertEquals(sk.getK(), k);
     assertEquals(sk.getN(), 1);
     assertEquals(sk.getNumRetained(), 1);
@@ -437,7 +437,7 @@ public void checkMemoryToStringFloatUpdatable() {
     s = KllPreambleUtil.toString(wmem, true);
     println("step 1: sketch to byte[]/memory & analyze memory");
     println(s);
-    sk2 = KllFloatsSketch.heapify(wmem);
+    sk2 = KllHeapFloatsSketch.heapifyImpl(wmem);
     upBytes2 = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(upBytes2);
     s = KllPreambleUtil.toString(wmem, true);
@@ -455,7 +455,7 @@ public void checkMemoryToStringFloatUpdatable() {
     s = KllPreambleUtil.toString(wmem, true);
     println("step 1: sketch to byte[]/memory & analyze memory");
     println(s);
-    sk2 = KllFloatsSketch.heapify(wmem);
+    sk2 = KllHeapFloatsSketch.heapifyImpl(wmem);
     upBytes2 = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(upBytes2);
     s = KllPreambleUtil.toString(wmem, true);
@@ -471,7 +471,7 @@ public void checkMemoryToStringFloatUpdatable() {
     s = KllPreambleUtil.toString(wmem, true);
     println("step 1: sketch to byte[]/memory & analyze memory");
     println(s);
-    sk2 = KllFloatsSketch.heapify(wmem);
+    sk2 = KllHeapFloatsSketch.heapifyImpl(wmem);
     upBytes2 = KllHelper.toUpdatableByteArrayImpl(sk2);
     wmem = WritableMemory.writableWrap(upBytes2);
     s = KllPreambleUtil.toString(wmem, true);