diff --git a/src/main/java/net/helenus/core/AbstractEntityDraft.java b/src/main/java/net/helenus/core/AbstractEntityDraft.java
index 40075ec..8f2a449 100644
--- a/src/main/java/net/helenus/core/AbstractEntityDraft.java
+++ b/src/main/java/net/helenus/core/AbstractEntityDraft.java
@@ -51,12 +51,7 @@ public abstract class AbstractEntityDraft<E> implements Drafted<E> {
       } else {
         // Collections fetched from the entityMap
         if (value instanceof Collection) {
-          try {
-            value = MappingUtil.<T>clone(value);
-          } catch (CloneNotSupportedException e) {
-            // TODO(gburd): deep?shallow? copy of List, Map, Set to a mutable collection.
-            value = (T) SerializationUtils.<Serializable>clone((Serializable) value);
-          }
+          value = (T) SerializationUtils.<Serializable>clone((Serializable) value);
         }
       }
     }
diff --git a/src/main/java/net/helenus/core/AbstractUnitOfWork.java b/src/main/java/net/helenus/core/AbstractUnitOfWork.java
index 3025a73..b9f5b27 100644
--- a/src/main/java/net/helenus/core/AbstractUnitOfWork.java
+++ b/src/main/java/net/helenus/core/AbstractUnitOfWork.java
@@ -22,6 +22,7 @@ import com.google.common.base.Stopwatch;
 import com.google.common.collect.HashBasedTable;
 import com.google.common.collect.Table;
 import com.google.common.collect.TreeTraverser;
+import java.io.Serializable;
 import java.util.*;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
@@ -30,9 +31,9 @@ import net.helenus.core.cache.CacheUtil;
 import net.helenus.core.cache.Facet;
 import net.helenus.core.operation.AbstractOperation;
 import net.helenus.core.operation.BatchOperation;
-import net.helenus.core.reflect.Drafted;
 import net.helenus.mapping.MappingUtil;
 import net.helenus.support.Either;
+import org.apache.commons.lang3.SerializationUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -218,15 +219,11 @@ public abstract class AbstractUnitOfWork<E extends Exception>
     result = checkParentCache(facets);
     if (result.isPresent()) {
       Object r = result.get();
-      try {
-        Class<?> iface = MappingUtil.getMappingInterface(r);
-        if (Drafted.class.isAssignableFrom(iface)) {
-          cacheUpdate(r, facets);
-        } else {
-          cacheUpdate(MappingUtil.clone(r), facets);
-        }
-      } catch (CloneNotSupportedException e) {
-        result = Optional.empty();
+      Class<?> iface = MappingUtil.getMappingInterface(r);
+      if (Helenus.entity(iface).isDraftable()) {
+        cacheUpdate(r, facets);
+      } else {
+        cacheUpdate(SerializationUtils.<Serializable>clone((Serializable) r), facets);
       }
     }
     return result;
diff --git a/src/main/java/net/helenus/core/operation/AbstractOptionalOperation.java b/src/main/java/net/helenus/core/operation/AbstractOptionalOperation.java
index 911383f..afe577d 100644
--- a/src/main/java/net/helenus/core/operation/AbstractOptionalOperation.java
+++ b/src/main/java/net/helenus/core/operation/AbstractOptionalOperation.java
@@ -24,18 +24,20 @@ import com.google.common.base.Function;
 import com.google.common.base.Stopwatch;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
+import java.io.Serializable;
 import java.util.List;
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionException;
 import java.util.concurrent.TimeoutException;
 import net.helenus.core.AbstractSessionOperations;
+import net.helenus.core.Helenus;
 import net.helenus.core.UnitOfWork;
 import net.helenus.core.cache.CacheUtil;
 import net.helenus.core.cache.Facet;
-import net.helenus.core.reflect.Drafted;
 import net.helenus.mapping.MappingUtil;
 import net.helenus.support.Fun;
+import org.apache.commons.lang3.SerializationUtils;
 
 public abstract class AbstractOptionalOperation<E, O extends AbstractOptionalOperation<E, O>>
     extends AbstractStatementOperation<E, O> {
@@ -153,26 +155,22 @@ public abstract class AbstractOptionalOperation<E, O extends AbstractOptionalOpe
                   cachedResult = (E) sessionOps.checkCache(tableName, facets);
                   if (cachedResult != null) {
                     Class<?> iface = MappingUtil.getMappingInterface(cachedResult);
-                    try {
-                      if (Drafted.class.isAssignableFrom(iface)) {
-                        result = Optional.of(cachedResult);
-                      } else {
-                        result = Optional.of(MappingUtil.clone(cachedResult));
-                      }
-                      sessionCacheHits.mark();
-                      cacheHits.mark();
-                      uow.recordCacheAndDatabaseOperationCount(1, 0);
-                    } catch (CloneNotSupportedException e) {
-                      result = Optional.empty();
-                      sessionCacheMiss.mark();
-                      cacheMiss.mark();
-                      uow.recordCacheAndDatabaseOperationCount(-1, 0);
-                    } finally {
-                      if (result.isPresent()) {
-                        updateCache = true;
-                      } else {
-                        updateCache = false;
-                      }
+                    if (Helenus.entity(iface).isDraftable()) {
+                      result = Optional.of(cachedResult);
+                    } else {
+                      result =
+                          Optional.of(
+                              (E)
+                                  SerializationUtils.<Serializable>clone(
+                                      (Serializable) cachedResult));
+                    }
+                    sessionCacheHits.mark();
+                    cacheHits.mark();
+                    uow.recordCacheAndDatabaseOperationCount(1, 0);
+                    if (result.isPresent()) {
+                      updateCache = true;
+                    } else {
+                      updateCache = false;
                     }
                   } else {
                     updateCache = false;
diff --git a/src/main/java/net/helenus/core/operation/AbstractStreamOperation.java b/src/main/java/net/helenus/core/operation/AbstractStreamOperation.java
index f0dac94..07b5649 100644
--- a/src/main/java/net/helenus/core/operation/AbstractStreamOperation.java
+++ b/src/main/java/net/helenus/core/operation/AbstractStreamOperation.java
@@ -24,6 +24,7 @@ import com.google.common.base.Function;
 import com.google.common.base.Stopwatch;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
@@ -31,12 +32,13 @@ import java.util.concurrent.CompletionException;
 import java.util.concurrent.TimeoutException;
 import java.util.stream.Stream;
 import net.helenus.core.AbstractSessionOperations;
+import net.helenus.core.Helenus;
 import net.helenus.core.UnitOfWork;
 import net.helenus.core.cache.CacheUtil;
 import net.helenus.core.cache.Facet;
-import net.helenus.core.reflect.Drafted;
 import net.helenus.mapping.MappingUtil;
 import net.helenus.support.Fun;
+import org.apache.commons.lang3.SerializationUtils;
 
 public abstract class AbstractStreamOperation<E, O extends AbstractStreamOperation<E, O>>
     extends AbstractStatementOperation<E, O> {
@@ -160,26 +162,20 @@ public abstract class AbstractStreamOperation<E, O extends AbstractStreamOperati
                   if (cachedResult != null) {
                     Class<?> iface = MappingUtil.getMappingInterface(cachedResult);
                     E result = null;
-                    try {
-                      if (Drafted.class.isAssignableFrom(iface)) {
-                        result = cachedResult;
-                      } else {
-                        result = MappingUtil.clone(cachedResult);
-                      }
-                      resultStream = Stream.of(result);
-                      sessionCacheHits.mark();
-                      cacheHits.mark();
-                      uow.recordCacheAndDatabaseOperationCount(1, 0);
-                    } catch (CloneNotSupportedException e) {
-                      resultStream = null;
-                      sessionCacheMiss.mark();
-                      uow.recordCacheAndDatabaseOperationCount(-1, 0);
-                    } finally {
-                      if (result != null) {
-                        updateCache = true;
-                      } else {
-                        updateCache = false;
-                      }
+                    if (Helenus.entity(iface).isDraftable()) {
+                      result = cachedResult;
+                    } else {
+                      result =
+                          (E) SerializationUtils.<Serializable>clone((Serializable) cachedResult);
+                    }
+                    resultStream = Stream.of(result);
+                    sessionCacheHits.mark();
+                    cacheHits.mark();
+                    uow.recordCacheAndDatabaseOperationCount(1, 0);
+                    if (result != null) {
+                      updateCache = true;
+                    } else {
+                      updateCache = false;
                     }
                   } else {
                     updateCache = false;
diff --git a/src/main/java/net/helenus/core/operation/InsertOperation.java b/src/main/java/net/helenus/core/operation/InsertOperation.java
index 5676c01..3547f82 100644
--- a/src/main/java/net/helenus/core/operation/InsertOperation.java
+++ b/src/main/java/net/helenus/core/operation/InsertOperation.java
@@ -31,7 +31,6 @@ import net.helenus.core.cache.CacheUtil;
 import net.helenus.core.cache.Facet;
 import net.helenus.core.cache.UnboundFacet;
 import net.helenus.core.reflect.DefaultPrimitiveTypes;
-import net.helenus.core.reflect.Drafted;
 import net.helenus.core.reflect.HelenusPropertyNode;
 import net.helenus.core.reflect.MapExportable;
 import net.helenus.mapping.HelenusEntity;
@@ -211,7 +210,7 @@ public final class InsertOperation<T> extends AbstractOperation<T, InsertOperati
 
   private T newInstance(Class<?> iface) {
     if (values.size() > 0) {
-      boolean immutable = iface.isAssignableFrom(Drafted.class);
+      boolean immutable = entity.isDraftable();
       Collection<HelenusProperty> properties = entity.getOrderedProperties();
       Map<String, Object> backingMap = new HashMap<String, Object>(properties.size());
 
diff --git a/src/main/java/net/helenus/core/operation/UpdateOperation.java b/src/main/java/net/helenus/core/operation/UpdateOperation.java
index 6288baa..fa946a2 100644
--- a/src/main/java/net/helenus/core/operation/UpdateOperation.java
+++ b/src/main/java/net/helenus/core/operation/UpdateOperation.java
@@ -203,7 +203,9 @@ public final class UpdateOperation<E> extends AbstractFilterOperation<E, UpdateO
       facet = new BoundFacet(prop, list);
     } else if (draft != null) {
       String key = prop.getPropertyName();
-      list = (List<V>) draftMap.get(key);
+      list =
+          (List<V>) new ArrayList<V>((List<V>) draftMap.get(key)); // copy immutable -> mutable list
+      draft.put(key, list);
       list.add(0, value);
       facet = new BoundFacet(prop, list);
     } else {
@@ -235,7 +237,9 @@ public final class UpdateOperation<E> extends AbstractFilterOperation<E, UpdateO
       facet = new BoundFacet(prop, list);
     } else if (draft != null && value.size() > 0) {
       String key = p.getProperty().getPropertyName();
-      list = (List<V>) draftMap.get(key);
+      list =
+          (List<V>) new ArrayList<V>((List<V>) draftMap.get(key)); // copy immutable -> mutable list
+      draft.put(key, list);
       list.addAll(0, value);
       facet = new BoundFacet(prop, list);
     } else {
@@ -266,7 +270,10 @@ public final class UpdateOperation<E> extends AbstractFilterOperation<E, UpdateO
         list = (List<V>) BeanColumnValueProvider.INSTANCE.getColumnValue(pojo, -1, prop, false);
       } else {
         String key = prop.getPropertyName();
-        list = (List<V>) draftMap.get(key);
+        list =
+            (List<V>)
+                new ArrayList<V>((List<V>) draftMap.get(key)); // copy immutable -> mutable list
+        draft.put(key, list);
       }
       if (idx < 0) {
         list.add(0, value);
@@ -305,7 +312,9 @@ public final class UpdateOperation<E> extends AbstractFilterOperation<E, UpdateO
       facet = new BoundFacet(prop, list);
     } else if (draft != null) {
       String key = prop.getPropertyName();
-      list = (List<V>) draftMap.get(key);
+      list =
+          (List<V>) new ArrayList<V>((List<V>) draftMap.get(key)); // copy immutable -> mutable list
+      draft.put(key, list);
       list.add(value);
       facet = new BoundFacet(prop, list);
     } else {
@@ -336,7 +345,9 @@ public final class UpdateOperation<E> extends AbstractFilterOperation<E, UpdateO
       facet = new BoundFacet(prop, list);
     } else if (draft != null && value.size() > 0) {
       String key = prop.getPropertyName();
-      list = (List<V>) draftMap.get(key);
+      list =
+          (List<V>) new ArrayList<V>((List<V>) draftMap.get(key)); // copy immutable -> mutable list
+      draft.put(key, list);
       list.addAll(value);
       facet = new BoundFacet(prop, list);
     } else {
@@ -367,7 +378,9 @@ public final class UpdateOperation<E> extends AbstractFilterOperation<E, UpdateO
       facet = new BoundFacet(prop, list);
     } else if (draft != null) {
       String key = prop.getPropertyName();
-      list = (List<V>) draftMap.get(key);
+      list =
+          (List<V>) new ArrayList<V>((List<V>) draftMap.get(key)); // copy immutable -> mutable list
+      draft.put(key, list);
       list.remove(value);
       facet = new BoundFacet(prop, list);
     } else {
@@ -398,7 +411,9 @@ public final class UpdateOperation<E> extends AbstractFilterOperation<E, UpdateO
       facet = new BoundFacet(prop, list);
     } else if (draft != null) {
       String key = prop.getPropertyName();
-      list = (List<V>) draftMap.get(key);
+      list =
+          (List<V>) new ArrayList<V>((List<V>) draftMap.get(key)); // copy immutable -> mutable list
+      draft.put(key, list);
       list.removeAll(value);
       facet = new BoundFacet(prop, list);
     } else {
@@ -467,7 +482,8 @@ public final class UpdateOperation<E> extends AbstractFilterOperation<E, UpdateO
       facet = new BoundFacet(prop, set);
     } else if (draft != null) {
       String key = prop.getPropertyName();
-      set = (Set<V>) draftMap.get(key);
+      set = (Set<V>) new HashSet<V>((Set<V>) draftMap.get(key));
+      draft.put(key, set);
       set.add(value);
       facet = new BoundFacet(prop, set);
     } else {
diff --git a/src/main/java/net/helenus/mapping/HelenusEntity.java b/src/main/java/net/helenus/mapping/HelenusEntity.java
index b19fee6..9ec0744 100644
--- a/src/main/java/net/helenus/mapping/HelenusEntity.java
+++ b/src/main/java/net/helenus/mapping/HelenusEntity.java
@@ -34,4 +34,6 @@ public interface HelenusEntity {
   HelenusProperty getProperty(String name);
 
   List<Facet> getFacets();
+
+  boolean isDraftable();
 }
diff --git a/src/main/java/net/helenus/mapping/HelenusMappingEntity.java b/src/main/java/net/helenus/mapping/HelenusMappingEntity.java
index 989a010..965178d 100644
--- a/src/main/java/net/helenus/mapping/HelenusMappingEntity.java
+++ b/src/main/java/net/helenus/mapping/HelenusMappingEntity.java
@@ -39,6 +39,7 @@ public final class HelenusMappingEntity implements HelenusEntity {
   private final HelenusEntityType type;
   private final IdentityName name;
   private final boolean cacheable;
+  private final boolean draftable;
   private final ImmutableMap<String, Method> methods;
   private final ImmutableMap<String, HelenusProperty> props;
   private final ImmutableList<HelenusProperty> orderedProps;
@@ -112,6 +113,16 @@ public final class HelenusMappingEntity implements HelenusEntity {
     // Caching
     cacheable = (null != iface.getDeclaredAnnotation(Cacheable.class));
 
+    // Draft
+    Class<?> draft;
+    try {
+      draft = Class.forName(iface.getName() + "$Draft");
+    } catch (Exception ignored) {
+      draft = null;
+    }
+    draftable = (draft != null);
+
+    // Materialized view
     List<HelenusProperty> primaryKeyProperties = new ArrayList<>();
     ImmutableList.Builder<Facet> facetsBuilder = ImmutableList.builder();
     if (iface.getDeclaredAnnotation(MaterializedView.class) == null) {
@@ -212,6 +223,11 @@ public final class HelenusMappingEntity implements HelenusEntity {
     return cacheable;
   }
 
+  @Override
+  public boolean isDraftable() {
+    return draftable;
+  }
+
   @Override
   public Class<?> getMappingInterface() {
     return iface;
diff --git a/src/main/java/net/helenus/mapping/MappingUtil.java b/src/main/java/net/helenus/mapping/MappingUtil.java
index 08b4bac..bb68587 100644
--- a/src/main/java/net/helenus/mapping/MappingUtil.java
+++ b/src/main/java/net/helenus/mapping/MappingUtil.java
@@ -16,7 +16,6 @@
 package net.helenus.mapping;
 
 import java.lang.annotation.Annotation;
-import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.List;
@@ -305,28 +304,6 @@ public final class MappingUtil {
     }
   }
 
-  // https://stackoverflow.com/a/4882306/366692
-  public static <T> T clone(T object) throws CloneNotSupportedException {
-    Object clone = null;
-
-    // Use reflection, because there is no other way
-    try {
-      Method method = object.getClass().getMethod("clone");
-      clone = method.invoke(object);
-    } catch (InvocationTargetException e) {
-      rethrow(e.getCause());
-    } catch (Exception cause) {
-      rethrow(cause);
-    }
-    if (object.getClass().isInstance(clone)) {
-      @SuppressWarnings("unchecked") // clone class <= object class <= T
-      T t = (T) clone;
-      return t;
-    } else {
-      throw new ClassCastException(clone.getClass().getName());
-    }
-  }
-
   private static void rethrow(Throwable cause) throws CloneNotSupportedException {
     if (cause instanceof RuntimeException) {
       throw (RuntimeException) cause;
diff --git a/src/main/java/net/helenus/mapping/value/ValueProviderMap.java b/src/main/java/net/helenus/mapping/value/ValueProviderMap.java
index 43e6318..eb1388c 100644
--- a/src/main/java/net/helenus/mapping/value/ValueProviderMap.java
+++ b/src/main/java/net/helenus/mapping/value/ValueProviderMap.java
@@ -19,7 +19,6 @@ import java.util.Collection;
 import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
-import net.helenus.core.reflect.Drafted;
 import net.helenus.mapping.HelenusEntity;
 import net.helenus.mapping.HelenusProperty;
 import net.helenus.support.HelenusMappingException;
@@ -35,7 +34,7 @@ public final class ValueProviderMap implements Map<String, Object> {
     this.source = source;
     this.valueProvider = valueProvider;
     this.entity = entity;
-    this.immutable = entity.getMappingInterface().isAssignableFrom(Drafted.class);
+    this.immutable = entity.isDraftable();
   }
 
   private static void throwShouldNeverCall(String methodName) {
diff --git a/src/test/java/net/helenus/test/integration/core/draft/Inventory.java b/src/test/java/net/helenus/test/integration/core/draft/Inventory.java
index 2c4f397..23ec43f 100644
--- a/src/test/java/net/helenus/test/integration/core/draft/Inventory.java
+++ b/src/test/java/net/helenus/test/integration/core/draft/Inventory.java
@@ -9,7 +9,7 @@ import net.helenus.core.reflect.MapExportable;
 import net.helenus.mapping.annotation.*;
 
 @Table
-public interface Inventory extends Entity, Drafted<Inventory> {
+public interface Inventory extends Entity {
 
   static Inventory inventory = Helenus.dsl(Inventory.class);
 
@@ -38,7 +38,7 @@ public interface Inventory extends Entity, Drafted<Inventory> {
     return new Draft(this);
   }
 
-  class Draft extends AbstractAuditedEntityDraft<Inventory> {
+  class Draft extends AbstractAuditedEntityDraft<Inventory> implements Drafted<Inventory> {
 
     // Entity/Draft pattern-enabling methods:
     Draft(UUID id) {
diff --git a/src/test/java/net/helenus/test/integration/core/draft/Supply.java b/src/test/java/net/helenus/test/integration/core/draft/Supply.java
index 7a28ad2..3b382cc 100644
--- a/src/test/java/net/helenus/test/integration/core/draft/Supply.java
+++ b/src/test/java/net/helenus/test/integration/core/draft/Supply.java
@@ -15,7 +15,7 @@ import net.helenus.mapping.annotation.*;
 
 @Table
 @Cacheable
-public interface Supply extends Entity, Drafted<Supply> {
+public interface Supply extends Entity {
 
   static Supply supply = Helenus.dsl(Supply.class);
 
@@ -52,8 +52,7 @@ public interface Supply extends Entity, Drafted<Supply> {
     return new Draft(this);
   }
 
-  class Draft extends AbstractEntityDraft<Supply> {
-
+  class Draft extends AbstractEntityDraft<Supply> implements Drafted<Supply> {
     // Entity/Draft pattern-enabling methods:
     Draft(String region) {
       super(null);
diff --git a/src/test/java/net/helenus/test/integration/core/unitofwork/UnitOfWorkTest.java b/src/test/java/net/helenus/test/integration/core/unitofwork/UnitOfWorkTest.java
index 830732a..fee366a 100644
--- a/src/test/java/net/helenus/test/integration/core/unitofwork/UnitOfWorkTest.java
+++ b/src/test/java/net/helenus/test/integration/core/unitofwork/UnitOfWorkTest.java
@@ -19,6 +19,7 @@ import static net.helenus.core.Query.eq;
 
 import com.datastax.driver.core.ConsistencyLevel;
 import com.datastax.driver.core.utils.UUIDs;
+import java.io.Serializable;
 import java.util.Date;
 import java.util.UUID;
 import net.bytebuddy.utility.RandomString;
@@ -38,7 +39,7 @@ import org.junit.Test;
 
 @Table
 @Cacheable
-interface Widget extends Entity {
+interface Widget extends Entity, Serializable {
   @PartitionKey
   UUID id();
 
diff --git a/src/test/java/net/helenus/test/unit/core/dsl/Account.java b/src/test/java/net/helenus/test/unit/core/dsl/Account.java
index 626363f..06d7ba5 100644
--- a/src/test/java/net/helenus/test/unit/core/dsl/Account.java
+++ b/src/test/java/net/helenus/test/unit/core/dsl/Account.java
@@ -39,7 +39,7 @@ public interface Account {
     return new Draft();
   }
 
-  class Draft implements Drafted { // TODO
+  class Draft implements Drafted<Account> {
 
     @Override
     public Set<String> mutated() {
@@ -47,7 +47,7 @@ public interface Account {
     }
 
     @Override
-    public Object build() {
+    public Account build() {
       return null;
     }