Experimental Feature - Freeze and detach beans (and attach)

- Frozen beans as ReadOnly + Unmodifiable collections
- Add Transaction.freezeAndDetach() returning FrozenBeans
- Add Transaction.attach( FrozenBeans )

- InterceptReadOnly now supports lazy loading
- Query.setReadOnly(true) now uses InterceptReadOnly [when it used to ALSO require Query.setDisableLazyLoading(true)}
- Add EntityBeanIntercept.errorOnLazyLoad (such that lazy loading on frozen bean is an error)

- BeanList, BeanSet, BeanMap are now freezable
- ModifyAwareList Set and Map are now freezable

ebean-api/src/main/java/io/ebean/ModifyAwareType.java

@@ -16,4 +16,9 @@ public interface ModifyAwareType {
    */
   void setMarkedDirty(boolean markedDirty);
 
+  /**
+   * Return a unmodifiable version of this type.
+   */
+  Object freeze();
+
 }

ebean-api/src/main/java/io/ebean/Transaction.java

@@ -2,6 +2,7 @@ package io.ebean;
 
 import io.ebean.annotation.DocStoreMode;
 import io.ebean.annotation.PersistBatch;
+import io.ebean.bean.FrozenBeans;
 import io.ebean.config.DatabaseConfig;
 import io.ebean.config.DocStoreConfig;
 
@@ -54,6 +55,24 @@ public interface Transaction extends AutoCloseable {
    */
   int SERIALIZABLE = java.sql.Connection.TRANSACTION_SERIALIZABLE;
 
+
+  /**
+   * Experimental Feature - Freeze the beans in the persistence context and detach them.
+   */
+  @Deprecated(since = "Experimental Feature")
+  default FrozenBeans freezeAndDetach() {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * Experimental Feature - Attach frozen beans to the persistence context so that they can be
+   * used with ORM queries (with the persistence context acting like a cache).
+   */
+  @Deprecated(since = "Experimental Feature")
+  default void attach(FrozenBeans frozenBeans) {
+    throw new UnsupportedOperationException();
+  }
+
   /**
    * Register a TransactionCallback with this transaction.
    */

ebean-api/src/main/java/io/ebean/bean/BeanCollection.java

@@ -35,6 +35,11 @@ public interface BeanCollection<E> extends Serializable, ToStringAware {
     ALL
   }
 
+  /**
+   * Return a unmodifiable collection of the underlying entities.
+   */
+  Object freeze();
+
   /**
    * Set the disableLazyLoad state.
    */

ebean-api/src/main/java/io/ebean/bean/EntityBeanIntercept.java

@@ -552,4 +552,16 @@ public interface EntityBeanIntercept extends Serializable {
    * Update the 'next' mutable info returning the content that was obtained via dirty detection.
    */
   String mutableNext(int propertyIndex);
+
+  /**
+   * Set that lazy loading if invoked throws a PersistenceException.
+   */
+  void errorOnLazyLoad(boolean lazyLoadAsError);
+
+  /**
+   * Freeze the intercept so that it is readOnly.
+   * Lazy loading and mutation of the bean is not allowed.
+   */
+  void freeze();
+
 }

ebean-api/src/main/java/io/ebean/bean/FrozenBeans.java

@@ -0,0 +1,9 @@
+package io.ebean.bean;
+
+import java.io.Serializable;
+
+/**
+ * Holds entity beans that are frozen.
+ */
+public interface FrozenBeans extends Serializable {
+}

ebean-api/src/main/java/io/ebean/bean/InterceptBase.java

@@ -0,0 +1,343 @@
+package io.ebean.bean;
+
+import io.ebean.DB;
+import io.ebean.Database;
+import jakarta.persistence.EntityNotFoundException;
+import jakarta.persistence.PersistenceException;
+
+import java.util.*;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * Base EntityBeanIntercept that supports partial loaded state and lazy loading.
+ */
+abstract class InterceptBase implements EntityBeanIntercept {
+
+  /**
+   * Flag for loaded property.
+   */
+  static final byte FLAG_LOADED_PROP = 1;
+
+  /**
+   * The actual entity bean that 'owns' this intercept.
+   */
+  protected final EntityBean owner;
+  protected final byte[] flags;
+  protected boolean readOnly;
+  protected boolean disableLazyLoad;
+  protected boolean errorOnLazyLoad;
+
+  private final ReentrantLock lock = new ReentrantLock();
+  private String ebeanServerName;
+  private transient BeanLoader beanLoader;
+  private transient PersistenceContext persistenceContext;
+
+  /**
+   * Flag set when lazy loading failed due to the underlying bean being deleted in the DB.
+   */
+  protected boolean lazyLoadFailure;
+  protected boolean fullyLoadedBean;
+  protected int lazyLoadProperty = -1;
+  protected Object ownerId;
+
+  /**
+   * Create with a given entity.
+   */
+  InterceptBase(Object ownerBean) {
+    this.owner = (EntityBean) ownerBean;
+    this.flags = new byte[owner._ebean_getPropertyNames().length];
+  }
+
+  /**
+   * EXPERIMENTAL - Constructor only for use by serialization frameworks.
+   */
+  InterceptBase() {
+    this.owner = null;
+    this.flags = null;
+  }
+
+  public void freeze() {
+    this.errorOnLazyLoad = true;
+    this.readOnly = true;
+    this.beanLoader = null;
+    this.persistenceContext = null;
+  }
+
+  @Override
+  public final EntityBean owner() {
+    return owner;
+  }
+
+  @Override
+  public final Object ownerId() {
+    return ownerId;
+  }
+
+  @Override
+  public final void setOwnerId(Object ownerId) {
+    this.ownerId = ownerId;
+  }
+
+  @Override
+  public final void setBeanLoader(BeanLoader beanLoader) {
+    this.beanLoader = beanLoader;
+    this.ebeanServerName = beanLoader.name();
+  }
+
+  @Override
+  public final void setBeanLoader(BeanLoader beanLoader, PersistenceContext ctx) {
+    this.beanLoader = beanLoader;
+    this.persistenceContext = ctx;
+    this.ebeanServerName = beanLoader.name();
+  }
+
+  @Override
+  public final PersistenceContext persistenceContext() {
+    return persistenceContext;
+  }
+
+  @Override
+  public final void setPersistenceContext(PersistenceContext persistenceContext) {
+    this.persistenceContext = persistenceContext;
+  }
+
+
+  @Override
+  public final boolean isFullyLoadedBean() {
+    return fullyLoadedBean;
+  }
+
+  @Override
+  public final void setFullyLoadedBean(boolean fullyLoadedBean) {
+    this.fullyLoadedBean = fullyLoadedBean;
+  }
+
+  @Override
+  public final boolean isPartial() {
+    for (byte flag : flags) {
+      if ((flag & FLAG_LOADED_PROP) == 0) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  @Override
+  public final boolean hasIdOnly(int idIndex) {
+    for (int i = 0; i < flags.length; i++) {
+      if (i == idIndex) {
+        if ((flags[i] & FLAG_LOADED_PROP) == 0) return false;
+      } else if ((flags[i] & FLAG_LOADED_PROP) != 0) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  @Override
+  public final boolean isReadOnly() {
+    return readOnly;
+  }
+
+  @Override
+  public final void setReadOnly(boolean readOnly) {
+    this.readOnly = readOnly;
+  }
+
+  @Override
+  public final void setLazyLoadFailure(Object ownerId) {
+    this.lazyLoadFailure = true;
+    this.ownerId = ownerId;
+  }
+
+  @Override
+  public final boolean isLazyLoadFailure() {
+    return lazyLoadFailure;
+  }
+
+  @Override
+  public final boolean isDisableLazyLoad() {
+    return disableLazyLoad;
+  }
+
+  @Override
+  public final void setDisableLazyLoad(boolean disableLazyLoad) {
+    this.disableLazyLoad = disableLazyLoad;
+  }
+
+  @Override
+  public final void errorOnLazyLoad(boolean errorOnLazyLoad) {
+    this.errorOnLazyLoad = errorOnLazyLoad;
+  }
+
+  @Override
+  public final void setEmbeddedLoaded(Object embeddedBean) {
+    if (embeddedBean instanceof EntityBean) {
+      ((EntityBean) embeddedBean)._ebean_getIntercept().setLoaded();
+    }
+  }
+
+  @Override
+  public final int findProperty(String propertyName) {
+    final String[] names = owner._ebean_getPropertyNames();
+    for (int i = 0; i < names.length; i++) {
+      if (names[i].equals(propertyName)) {
+        return i;
+      }
+    }
+    return -1;
+  }
+
+  @Override
+  public final String property(int propertyIndex) {
+    if (propertyIndex == -1) {
+      return null;
+    }
+    return owner._ebean_getPropertyName(propertyIndex);
+  }
+
+  @Override
+  public final int propertyLength() {
+    return flags.length;
+  }
+
+  @Override
+  public final void setPropertyLoaded(String propertyName, boolean loaded) {
+    final int position = findProperty(propertyName);
+    if (position == -1) {
+      throw new IllegalArgumentException("Property " + propertyName + " not found");
+    }
+    if (loaded) {
+      flags[position] |= FLAG_LOADED_PROP;
+    } else {
+      flags[position] &= ~FLAG_LOADED_PROP;
+    }
+  }
+
+  @Override
+  public final void setPropertyUnloaded(int propertyIndex) {
+    flags[propertyIndex] &= ~FLAG_LOADED_PROP;
+  }
+
+  @Override
+  public final void initialisedMany(int propertyIndex) {
+    flags[propertyIndex] |= FLAG_LOADED_PROP;
+  }
+
+  @Override
+  public final void setLoadedProperty(int propertyIndex) {
+    flags[propertyIndex] |= FLAG_LOADED_PROP;
+  }
+
+  @Override
+  public final void setLoadedPropertyAll() {
+    for (int i = 0; i < flags.length; i++) {
+      flags[i] |= FLAG_LOADED_PROP;
+    }
+  }
+
+  @Override
+  public final boolean isLoadedProperty(int propertyIndex) {
+    return (flags[propertyIndex] & FLAG_LOADED_PROP) != 0;
+  }
+
+  @Override
+  public final Set<String> loadedPropertyNames() {
+    if (fullyLoadedBean) {
+      return null;
+    }
+    final Set<String> props = new LinkedHashSet<>();
+    for (int i = 0; i < flags.length; i++) {
+      if ((flags[i] & FLAG_LOADED_PROP) != 0) {
+        props.add(property(i));
+      }
+    }
+    return props;
+  }
+
+
+  @Override
+  public final StringBuilder loadedPropertyKey() {
+    final StringBuilder sb = new StringBuilder();
+    final int len = propertyLength();
+    for (int i = 0; i < len; i++) {
+      if (isLoadedProperty(i)) {
+        sb.append(i).append(',');
+      }
+    }
+    return sb;
+  }
+
+  @Override
+  public final boolean[] loaded() {
+    final boolean[] ret = new boolean[flags.length];
+    for (int i = 0; i < ret.length; i++) {
+      ret[i] = (flags[i] & FLAG_LOADED_PROP) != 0;
+    }
+    return ret;
+  }
+
+  @Override
+  public final int lazyLoadPropertyIndex() {
+    return lazyLoadProperty;
+  }
+
+  @Override
+  public final String lazyLoadProperty() {
+    return property(lazyLoadProperty);
+  }
+
+  @Override
+  public final void loadBean(int loadProperty) {
+    lock.lock();
+    try {
+      if (errorOnLazyLoad) {
+        throw new PersistenceException("Lazy loading not allowed on this bean");
+      }
+      if (beanLoader == null) {
+        final Database database = DB.byName(ebeanServerName);
+        if (database == null) {
+          throw new PersistenceException(ebeanServerName == null ? "No registered default server" : "Database [" + ebeanServerName + "] is not registered");
+        }
+        // For stand alone reference bean or after deserialisation lazy load
+        // using the ebeanServer. Synchronise only on the bean.
+        loadBeanInternal(loadProperty, database.pluginApi().beanLoader());
+        return;
+      }
+    } finally {
+      lock.unlock();
+    }
+    final Lock lock = beanLoader.lock();
+    try {
+      // Lazy loading using LoadBeanContext which supports batch loading
+      // Synchronise on the beanLoader (a 'node' of the LoadBeanContext 'tree')
+      loadBeanInternal(loadProperty, beanLoader);
+    } finally {
+      lock.unlock();
+    }
+  }
+
+  @Override
+  public final void loadBeanInternal(int loadProperty, BeanLoader loader) {
+    if ((flags[loadProperty] & FLAG_LOADED_PROP) != 0) {
+      // race condition where multiple threads calling preGetter concurrently
+      return;
+    }
+    if (lazyLoadFailure) {
+      // failed when batch lazy loaded by another bean in the batch
+      throw new EntityNotFoundException("(Lazy) loading failed on type:" + owner.getClass().getName() + " id:" + ownerId + " - Bean has been deleted. BeanLoader: " + beanLoader);
+    }
+    if (lazyLoadProperty == -1) {
+      lazyLoadProperty = loadProperty;
+      loader.loadBean(this);
+      if (lazyLoadFailure) {
+        // failed when lazy loading this bean
+        throw new EntityNotFoundException("Lazy loading failed on type:" + owner.getClass().getName() + " id:" + ownerId + " - Bean has been deleted. BeanLoader: " + beanLoader);
+      }
+      // bean should be loaded and intercepting now. setLoaded() has
+      // been called by the lazy loading mechanism
+    }
+  }
+
+}

ebean-api/src/main/java/io/ebean/bean/InterceptReadOnly.java

@@ -10,55 +10,110 @@ import java.util.Set;
  * EntityBeanIntercept optimised for read only use.
  * <p>
  * For the read only use this intercept doesn't need to hold any state that is normally
- * required for updates such as per property changed, loaded, dirty state, original values
+ * required for updates such as per property changed, dirty state, original values
  * bean state etc.
  */
-public class InterceptReadOnly implements EntityBeanIntercept {
-
-  private final EntityBean owner;
+public final class InterceptReadOnly extends InterceptBase {
 
   /**
    * Create with a given entity.
    */
   public InterceptReadOnly(Object ownerBean) {
-    this.owner = (EntityBean) ownerBean;
+    super(ownerBean);
   }
 
   @Override
-  public String toString() {
-    return "InterceptReadOnly{" + owner + '}';
+  public void preGetId() {
+    // do nothing
   }
 
   @Override
-  public EntityBean owner() {
-    return owner;
+  public void preGetter(int propertyIndex) {
+    if (disableLazyLoad) {
+      return;
+    }
+    if (!isLoadedProperty(propertyIndex)) {
+      loadBean(propertyIndex);
+    }
+  }
+
+  private void preSetter(int propertyIndex) {
+    if (readOnly) {
+      throw new IllegalStateException("This bean is readOnly");
+    }
+    setLoadedProperty(propertyIndex);
   }
 
   @Override
-  public PersistenceContext persistenceContext() {
-    return null;
+  public void preSetterMany(boolean interceptField, int propertyIndex, Object oldValue, Object newValue) {
+    preSetter(propertyIndex);
   }
 
   @Override
-  public void setPersistenceContext(PersistenceContext persistenceContext) {
-
+  public void preSetter(boolean intercept, int propertyIndex, Object oldValue, Object newValue) {
+    preSetter(propertyIndex);
   }
 
+  @Override
+  public void preSetter(boolean intercept, int propertyIndex, boolean oldValue, boolean newValue) {
+    preSetter(propertyIndex);
+  }
+
+  @Override
+  public void preSetter(boolean intercept, int propertyIndex, int oldValue, int newValue) {
+    preSetter(propertyIndex);
+  }
+
+  @Override
+  public void preSetter(boolean intercept, int propertyIndex, long oldValue, long newValue) {
+    preSetter(propertyIndex);
+  }
+
+  @Override
+  public void preSetter(boolean intercept, int propertyIndex, double oldValue, double newValue) {
+    preSetter(propertyIndex);
+  }
+
+  @Override
+  public void preSetter(boolean intercept, int propertyIndex, float oldValue, float newValue) {
+    preSetter(propertyIndex);
+  }
+
+  @Override
+  public void preSetter(boolean intercept, int propertyIndex, short oldValue, short newValue) {
+    preSetter(propertyIndex);
+  }
+
+  @Override
+  public void preSetter(boolean intercept, int propertyIndex, char oldValue, char newValue) {
+    preSetter(propertyIndex);
+  }
+
+  @Override
+  public void preSetter(boolean intercept, int propertyIndex, byte oldValue, byte newValue) {
+    preSetter(propertyIndex);
+  }
+
+  @Override
+  public void preSetter(boolean intercept, int propertyIndex, char[] oldValue, char[] newValue) {
+    preSetter(propertyIndex);
+  }
+
+  @Override
+  public void preSetter(boolean intercept, int propertyIndex, byte[] oldValue, byte[] newValue) {
+    preSetter(propertyIndex);
+  }
+
+
+  // ------------------------------------------------------------------------------------
+  // The following method have "Do Nothing" behaviour as not interested in mutation state
+  // ------------------------------------------------------------------------------------
+
   @Override
   public void setNodeUsageCollector(NodeUsageCollector usageCollector) {
 
   }
 
-  @Override
-  public Object ownerId() {
-    return null;
-  }
-
-  @Override
-  public void setOwnerId(Object ownerId) {
-
-  }
-
   @Override
   public Object embeddedOwner() {
     return null;
@@ -84,31 +139,6 @@ public class InterceptReadOnly implements EntityBeanIntercept {
 
   }
 
-  @Override
-  public void setBeanLoader(BeanLoader beanLoader, PersistenceContext ctx) {
-
-  }
-
-  @Override
-  public void setBeanLoader(BeanLoader beanLoader) {
-
-  }
-
-  @Override
-  public boolean isFullyLoadedBean() {
-    return false;
-  }
-
-  @Override
-  public void setFullyLoadedBean(boolean fullyLoadedBean) {
-
-  }
-
-  @Override
-  public boolean isPartial() {
-    return false;
-  }
-
   @Override
   public boolean isDirty() {
     return false;
@@ -134,11 +164,6 @@ public class InterceptReadOnly implements EntityBeanIntercept {
     return false;
   }
 
-  @Override
-  public boolean hasIdOnly(int idIndex) {
-    return false;
-  }
-
   @Override
   public boolean isReference() {
     return false;
@@ -159,16 +184,6 @@ public class InterceptReadOnly implements EntityBeanIntercept {
     return false;
   }
 
-  @Override
-  public boolean isReadOnly() {
-    return true;
-  }
-
-  @Override
-  public void setReadOnly(boolean readOnly) {
-
-  }
-
   @Override
   public void setForceUpdate(boolean forceUpdate) {
 
@@ -199,31 +214,6 @@ public class InterceptReadOnly implements EntityBeanIntercept {
 
   }
 
-  @Override
-  public void setLazyLoadFailure(Object ownerId) {
-
-  }
-
-  @Override
-  public boolean isLazyLoadFailure() {
-    return false;
-  }
-
-  @Override
-  public boolean isDisableLazyLoad() {
-    return false;
-  }
-
-  @Override
-  public void setDisableLazyLoad(boolean disableLazyLoad) {
-
-  }
-
-  @Override
-  public void setEmbeddedLoaded(Object embeddedBean) {
-
-  }
-
   @Override
   public boolean isEmbeddedNewOrDirty(Object embeddedBean) {
     return false;
@@ -234,45 +224,6 @@ public class InterceptReadOnly implements EntityBeanIntercept {
     return null;
   }
 
-  @Override
-  public int findProperty(String propertyName) {
-    return 0;
-  }
-
-  @Override
-  public String property(int propertyIndex) {
-    return null;
-  }
-
-  @Override
-  public int propertyLength() {
-    return 0;
-  }
-
-  @Override
-  public void setPropertyLoaded(String propertyName, boolean loaded) {
-
-  }
-
-  @Override
-  public void setPropertyUnloaded(int propertyIndex) {
-
-  }
-
-  @Override
-  public void setLoadedProperty(int propertyIndex) {
-
-  }
-
-  @Override
-  public void setLoadedPropertyAll() {
-
-  }
-
-  @Override
-  public boolean isLoadedProperty(int propertyIndex) {
-    return false;
-  }
 
   @Override
   public boolean isChangedProperty(int propertyIndex) {
@@ -319,11 +270,6 @@ public class InterceptReadOnly implements EntityBeanIntercept {
 
   }
 
-  @Override
-  public Set<String> loadedPropertyNames() {
-    return Collections.emptySet();
-  }
-
   @Override
   public boolean[] dirtyProperties() {
     return new boolean[0];
@@ -369,61 +315,11 @@ public class InterceptReadOnly implements EntityBeanIntercept {
 
   }
 
-  @Override
-  public StringBuilder loadedPropertyKey() {
-    return null;
-  }
-
-  @Override
-  public boolean[] loaded() {
-    return new boolean[0];
-  }
-
-  @Override
-  public int lazyLoadPropertyIndex() {
-    return 0;
-  }
-
-  @Override
-  public String lazyLoadProperty() {
-    return null;
-  }
-
-  @Override
-  public void loadBean(int loadProperty) {
-
-  }
-
-  @Override
-  public void loadBeanInternal(int loadProperty, BeanLoader loader) {
-
-  }
-
-  @Override
-  public void initialisedMany(int propertyIndex) {
-
-  }
-
   @Override
   public void preGetterCallback(int propertyIndex) {
 
   }
 
-  @Override
-  public void preGetId() {
-
-  }
-
-  @Override
-  public void preGetter(int propertyIndex) {
-
-  }
-
-  @Override
-  public void preSetterMany(boolean interceptField, int propertyIndex, Object oldValue, Object newValue) {
-
-  }
-
   @Override
   public void setChangedPropertyValue(int propertyIndex, boolean setDirtyState, Object origValue) {
 
@@ -434,61 +330,6 @@ public class InterceptReadOnly implements EntityBeanIntercept {
 
   }
 
-  @Override
-  public void preSetter(boolean intercept, int propertyIndex, Object oldValue, Object newValue) {
-
-  }
-
-  @Override
-  public void preSetter(boolean intercept, int propertyIndex, boolean oldValue, boolean newValue) {
-
-  }
-
-  @Override
-  public void preSetter(boolean intercept, int propertyIndex, int oldValue, int newValue) {
-
-  }
-
-  @Override
-  public void preSetter(boolean intercept, int propertyIndex, long oldValue, long newValue) {
-
-  }
-
-  @Override
-  public void preSetter(boolean intercept, int propertyIndex, double oldValue, double newValue) {
-
-  }
-
-  @Override
-  public void preSetter(boolean intercept, int propertyIndex, float oldValue, float newValue) {
-
-  }
-
-  @Override
-  public void preSetter(boolean intercept, int propertyIndex, short oldValue, short newValue) {
-
-  }
-
-  @Override
-  public void preSetter(boolean intercept, int propertyIndex, char oldValue, char newValue) {
-
-  }
-
-  @Override
-  public void preSetter(boolean intercept, int propertyIndex, byte oldValue, byte newValue) {
-
-  }
-
-  @Override
-  public void preSetter(boolean intercept, int propertyIndex, char[] oldValue, char[] newValue) {
-
-  }
-
-  @Override
-  public void preSetter(boolean intercept, int propertyIndex, byte[] oldValue, byte[] newValue) {
-
-  }
-
   @Override
   public void setOldValue(int propertyIndex, Object oldValue) {
 

ebean-api/src/main/java/io/ebean/bean/InterceptReadWrite.java

@@ -1,11 +1,7 @@
 package io.ebean.bean;
 
-import io.ebean.DB;
-import io.ebean.Database;
 import io.ebean.ValuePair;
 
-import jakarta.persistence.EntityNotFoundException;
-import jakarta.persistence.PersistenceException;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -13,8 +9,6 @@ import java.io.InputStream;
 import java.math.BigDecimal;
 import java.net.URL;
 import java.util.*;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * This is the object added to every entity bean using byte code enhancement.
@@ -22,7 +16,7 @@ import java.util.concurrent.locks.ReentrantLock;
  * This provides the mechanisms to support deferred fetching of reference beans
  * and oldValues generation for concurrency checking.
  */
-public final class InterceptReadWrite implements EntityBeanIntercept {
+public final class InterceptReadWrite extends InterceptBase {
 
   private static final long serialVersionUID = -3664031775464862649L;
 
@@ -30,10 +24,6 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
   private static final int STATE_REFERENCE = 1;
   private static final int STATE_LOADED = 2;
 
-  /**
-   * Used when a bean is partially loaded.
-   */
-  private static final byte FLAG_LOADED_PROP = 1;
   private static final byte FLAG_CHANGED_PROP = 2;
   private static final byte FLAG_CHANGEDLOADED_PROP = 3;
   /**
@@ -47,43 +37,21 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
    */
   private static final byte FLAG_MUTABLE_HASH_SET = 16;
 
-  private final ReentrantLock lock = new ReentrantLock();
   private transient NodeUsageCollector nodeUsageCollector;
-  private transient PersistenceContext persistenceContext;
-  private transient BeanLoader beanLoader;
   private transient PreGetterCallback preGetterCallback;
 
-  private String ebeanServerName;
-  private boolean deletedFromCollection;
-
-  /**
-   * The actual entity bean that 'owns' this intercept.
-   */
-  private final EntityBean owner;
   private EntityBean embeddedOwner;
   private int embeddedOwnerIndex;
   /**
-   * One of NEW, REF, UPD.
+   * One of NEW, REF, LOADED.
    */
   private int state;
+  private boolean deletedFromCollection;
   private boolean forceUpdate;
-  private boolean readOnly;
   private boolean dirty;
-  /**
-   * Flag set to disable lazy loading.
-   */
-  private boolean disableLazyLoad;
-  /**
-   * Flag set when lazy loading failed due to the underlying bean being deleted in the DB.
-   */
-  private boolean lazyLoadFailure;
-  private boolean fullyLoadedBean;
   private boolean loadedFromCache;
-  private final byte[] flags;
   private Object[] origValues;
   private Exception[] loadErrors;
-  private int lazyLoadProperty = -1;
-  private Object ownerId;
   private int sortOrder;
 
   /**
@@ -101,49 +69,14 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
    * Create with a given entity.
    */
   public InterceptReadWrite(Object ownerBean) {
-    this.owner = (EntityBean) ownerBean;
-    this.flags = new byte[owner._ebean_getPropertyNames().length];
+    super(ownerBean);
   }
 
   /**
    * EXPERIMENTAL - Constructor only for use by serialization frameworks.
    */
   public InterceptReadWrite() {
-    this.owner = null;
-    this.flags = null;
-  }
-
-  @Override
-  public String toString() {
-    return "InterceptReadWrite@" + hashCode() + "{state=" + state +
-      (dirty ? " dirty;" : "") +
-      (forceUpdate ? " forceUpdate;" : "") +
-      (readOnly ? " readOnly;" : "") +
-      (disableLazyLoad ? " disableLazyLoad;" : "") +
-      (lazyLoadFailure ? " lazyLoadFailure;" : "") +
-      (fullyLoadedBean ? " fullyLoadedBean;" : "") +
-      (loadedFromCache ? " loadedFromCache;" : "") +
-      ", pc=" + System.identityHashCode(persistenceContext) +
-      ", flags=" + Arrays.toString(flags) +
-      (lazyLoadProperty > -1 ? (", lazyLoadProperty=" + lazyLoadProperty) : "") +
-      ", loader=" + beanLoader +
-      (ownerId != null ? (", ownerId=" + ownerId) : "") +
-      '}';
-  }
-
-  @Override
-  public EntityBean owner() {
-    return owner;
-  }
-
-  @Override
-  public PersistenceContext persistenceContext() {
-    return persistenceContext;
-  }
-
-  @Override
-  public void setPersistenceContext(PersistenceContext persistenceContext) {
-    this.persistenceContext = persistenceContext;
+    super();
   }
 
   @Override
@@ -151,16 +84,6 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
     this.nodeUsageCollector = usageCollector;
   }
 
-  @Override
-  public Object ownerId() {
-    return ownerId;
-  }
-
-  @Override
-  public void setOwnerId(Object ownerId) {
-    this.ownerId = ownerId;
-  }
-
   @Override
   public Object embeddedOwner() {
     return embeddedOwner;
@@ -187,39 +110,6 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
     this.embeddedOwnerIndex = embeddedOwnerIndex;
   }
 
-  @Override
-  public void setBeanLoader(BeanLoader beanLoader, PersistenceContext ctx) {
-    this.beanLoader = beanLoader;
-    this.persistenceContext = ctx;
-    this.ebeanServerName = beanLoader.name();
-  }
-
-  @Override
-  public void setBeanLoader(BeanLoader beanLoader) {
-    this.beanLoader = beanLoader;
-    this.ebeanServerName = beanLoader.name();
-  }
-
-  @Override
-  public boolean isFullyLoadedBean() {
-    return fullyLoadedBean;
-  }
-
-  @Override
-  public void setFullyLoadedBean(boolean fullyLoadedBean) {
-    this.fullyLoadedBean = fullyLoadedBean;
-  }
-
-  @Override
-  public boolean isPartial() {
-    for (byte flag : flags) {
-      if ((flag & FLAG_LOADED_PROP) == 0) {
-        return true;
-      }
-    }
-    return false;
-  }
-
   @Override
   public boolean isDirty() {
     if (dirty) {
@@ -257,18 +147,6 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
     return isNew() || isDirty();
   }
 
-  @Override
-  public boolean hasIdOnly(int idIndex) {
-    for (int i = 0; i < flags.length; i++) {
-      if (i == idIndex) {
-        if ((flags[i] & FLAG_LOADED_PROP) == 0) return false;
-      } else if ((flags[i] & FLAG_LOADED_PROP) != 0) {
-        return false;
-      }
-    }
-    return true;
-  }
-
   @Override
   public boolean isReference() {
     return state == STATE_REFERENCE;
@@ -298,16 +176,6 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
     return loadedFromCache;
   }
 
-  @Override
-  public boolean isReadOnly() {
-    return readOnly;
-  }
-
-  @Override
-  public void setReadOnly(boolean readOnly) {
-    this.readOnly = readOnly;
-  }
-
   @Override
   public void setForceUpdate(boolean forceUpdate) {
     this.forceUpdate = forceUpdate;
@@ -356,34 +224,6 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
     this.lazyLoadProperty = -1;
   }
 
-  @Override
-  public void setLazyLoadFailure(Object ownerId) {
-    this.lazyLoadFailure = true;
-    this.ownerId = ownerId;
-  }
-
-  @Override
-  public boolean isLazyLoadFailure() {
-    return lazyLoadFailure;
-  }
-
-  @Override
-  public boolean isDisableLazyLoad() {
-    return disableLazyLoad;
-  }
-
-  @Override
-  public void setDisableLazyLoad(boolean disableLazyLoad) {
-    this.disableLazyLoad = disableLazyLoad;
-  }
-
-  @Override
-  public void setEmbeddedLoaded(Object embeddedBean) {
-    if (embeddedBean instanceof EntityBean) {
-      ((EntityBean) embeddedBean)._ebean_getIntercept().setLoaded();
-    }
-  }
-
   @Override
   public boolean isEmbeddedNewOrDirty(Object embeddedBean) {
     if (embeddedBean == null) {
@@ -411,65 +251,6 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
     return origValues[propertyIndex];
   }
 
-  @Override
-  public int findProperty(String propertyName) {
-    final String[] names = owner._ebean_getPropertyNames();
-    for (int i = 0; i < names.length; i++) {
-      if (names[i].equals(propertyName)) {
-        return i;
-      }
-    }
-    return -1;
-  }
-
-  @Override
-  public String property(int propertyIndex) {
-    if (propertyIndex == -1) {
-      return null;
-    }
-    return owner._ebean_getPropertyName(propertyIndex);
-  }
-
-  @Override
-  public int propertyLength() {
-    return flags.length;
-  }
-
-  @Override
-  public void setPropertyLoaded(String propertyName, boolean loaded) {
-    final int position = findProperty(propertyName);
-    if (position == -1) {
-      throw new IllegalArgumentException("Property " + propertyName + " not found");
-    }
-    if (loaded) {
-      flags[position] |= FLAG_LOADED_PROP;
-    } else {
-      flags[position] &= ~FLAG_LOADED_PROP;
-    }
-  }
-
-  @Override
-  public void setPropertyUnloaded(int propertyIndex) {
-    flags[propertyIndex] &= ~FLAG_LOADED_PROP;
-  }
-
-  @Override
-  public void setLoadedProperty(int propertyIndex) {
-    flags[propertyIndex] |= FLAG_LOADED_PROP;
-  }
-
-  @Override
-  public void setLoadedPropertyAll() {
-    for (int i = 0; i < flags.length; i++) {
-      flags[i] |= FLAG_LOADED_PROP;
-    }
-  }
-
-  @Override
-  public boolean isLoadedProperty(int propertyIndex) {
-    return (flags[propertyIndex] & FLAG_LOADED_PROP) != 0;
-  }
-
   @Override
   public boolean isChangedProperty(int propertyIndex) {
     return (flags[propertyIndex] & FLAG_CHANGED_PROP) != 0;
@@ -530,20 +311,6 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
     setDirty(true);
   }
 
-  @Override
-  public Set<String> loadedPropertyNames() {
-    if (fullyLoadedBean) {
-      return null;
-    }
-    final Set<String> props = new LinkedHashSet<>();
-    for (int i = 0; i < flags.length; i++) {
-      if ((flags[i] & FLAG_LOADED_PROP) != 0) {
-        props.add(property(i));
-      }
-    }
-    return props;
-  }
-
   @Override
   public boolean[] dirtyProperties() {
     final int len = propertyLength();
@@ -668,86 +435,6 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
     }
   }
 
-  @Override
-  public StringBuilder loadedPropertyKey() {
-    final StringBuilder sb = new StringBuilder();
-    final int len = propertyLength();
-    for (int i = 0; i < len; i++) {
-      if (isLoadedProperty(i)) {
-        sb.append(i).append(',');
-      }
-    }
-    return sb;
-  }
-
-  @Override
-  public boolean[] loaded() {
-    final boolean[] ret = new boolean[flags.length];
-    for (int i = 0; i < ret.length; i++) {
-      ret[i] = (flags[i] & FLAG_LOADED_PROP) != 0;
-    }
-    return ret;
-  }
-
-  @Override
-  public int lazyLoadPropertyIndex() {
-    return lazyLoadProperty;
-  }
-
-  @Override
-  public String lazyLoadProperty() {
-    return property(lazyLoadProperty);
-  }
-
-  @Override
-  public void loadBean(int loadProperty) {
-    lock.lock();
-    try {
-      if (beanLoader == null) {
-        final Database database = DB.byName(ebeanServerName);
-        if (database == null) {
-          throw new PersistenceException(ebeanServerName == null ? "No registered default server" : "Database [" + ebeanServerName + "] is not registered");
-        }
-        // For stand alone reference bean or after deserialisation lazy load
-        // using the ebeanServer. Synchronise only on the bean.
-        loadBeanInternal(loadProperty, database.pluginApi().beanLoader());
-        return;
-      }
-    } finally {
-      lock.unlock();
-    }
-    final Lock lock = beanLoader.lock();
-    try {
-      // Lazy loading using LoadBeanContext which supports batch loading
-      // Synchronise on the beanLoader (a 'node' of the LoadBeanContext 'tree')
-      loadBeanInternal(loadProperty, beanLoader);
-    } finally {
-      lock.unlock();
-    }
-  }
-
-  @Override
-  public void loadBeanInternal(int loadProperty, BeanLoader loader) {
-    if ((flags[loadProperty] & FLAG_LOADED_PROP) != 0) {
-      // race condition where multiple threads calling preGetter concurrently
-      return;
-    }
-    if (lazyLoadFailure) {
-      // failed when batch lazy loaded by another bean in the batch
-      throw new EntityNotFoundException("(Lazy) loading failed on type:" + owner.getClass().getName() + " id:" + ownerId + " - Bean has been deleted. BeanLoader: " + beanLoader);
-    }
-    if (lazyLoadProperty == -1) {
-      lazyLoadProperty = loadProperty;
-      loader.loadBean(this);
-      if (lazyLoadFailure) {
-        // failed when lazy loading this bean
-        throw new EntityNotFoundException("Lazy loading failed on type:" + owner.getClass().getName() + " id:" + ownerId + " - Bean has been deleted. BeanLoader: " + beanLoader);
-      }
-      // bean should be loaded and intercepting now. setLoaded() has
-      // been called by the lazy loading mechanism
-    }
-  }
-
   /**
    * Helper method to check if two objects are equal.
    */
@@ -808,11 +495,6 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
     }
   }
 
-  @Override
-  public void initialisedMany(int propertyIndex) {
-    flags[propertyIndex] |= FLAG_LOADED_PROP;
-  }
-
   @Override
   public void preGetterCallback(int propertyIndex) {
     PreGetterCallback preGetterCallback = this.preGetterCallback;
@@ -1076,4 +758,16 @@ public final class InterceptReadWrite implements EntityBeanIntercept {
     final MutableValueNext next = mutableNext[propertyIndex];
     return next != null ? next.content() : null;
   }
+
+  @Override
+  public void freeze() {
+    super.freeze();
+    // not allowed to be used for updates
+    this.dirty = false;
+    this.forceUpdate = false;
+    this.deletedFromCollection = false;
+    this.origValues = null;
+    this.nodeUsageCollector = null;
+    this.embeddedOwner = null;
+  }
 }

ebean-api/src/main/java/io/ebean/common/BeanList.java

@@ -44,6 +44,11 @@ public final class BeanList<E> extends AbstractBeanCollection<E> implements List
     builder.addCollection(list);
   }
 
+  @Override
+  public Object freeze() {
+    return list == null ? Collections.emptyList() : Collections.unmodifiableList(list);
+  }
+
   @Override
   public void reset(EntityBean ownerBean, String propertyName) {
     this.ownerBean = ownerBean;

ebean-api/src/main/java/io/ebean/common/BeanMap.java

@@ -37,6 +37,11 @@ public final class BeanMap<K, E> extends AbstractBeanCollection<E> implements Ma
     super(ebeanServer, ownerBean, propertyName);
   }
 
+  @Override
+  public Object freeze() {
+    return map == null ? Collections.emptyMap() : Collections.unmodifiableMap(map);
+  }
+
   @Override
   public void toString(ToStringBuilder builder) {
     if (map == null || map.isEmpty()) {

ebean-api/src/main/java/io/ebean/common/BeanSet.java

@@ -3,10 +3,7 @@ package io.ebean.common;
 import io.ebean.bean.*;
 
 import java.io.Serializable;
-import java.util.Collection;
-import java.util.Iterator;
-import java.util.LinkedHashSet;
-import java.util.Set;
+import java.util.*;
 
 /**
  * Set capable of lazy loading and modification aware.
@@ -43,6 +40,11 @@ public final class BeanSet<E> extends AbstractBeanCollection<E> implements Set<E
     builder.addCollection(set);
   }
 
+  @Override
+  public Object freeze() {
+    return set == null ? Collections.emptySet() : Collections.unmodifiableSet(set);
+  }
+
   @Override
   public void reset(EntityBean ownerBean, String propertyName) {
     this.ownerBean = ownerBean;

ebean-core/src/main/java/io/ebeaninternal/api/SpiPersistenceContext.java

@@ -1,8 +1,11 @@
 package io.ebeaninternal.api;
 
+import io.ebean.bean.FrozenBeans;
+import io.ebean.bean.EntityBean;
 import io.ebean.bean.PersistenceContext;
 
 import java.util.List;
+import java.util.Map;
 
 /**
  * SPI extension to PersistenceContext.
@@ -14,4 +17,14 @@ public interface SpiPersistenceContext extends PersistenceContext {
    */
   List<Object> dirtyBeans(SpiBeanTypeManager manager);
 
+  /**
+   * Return all the entities from this persistence context.
+   */
+  Map<Class<?>, List<EntityBean>> detach();
+
+  /**
+   * Attach all the cached entities into this persistence context.
+   */
+  void attach(FrozenBeans cachedBeans);
+
 }

ebean-core/src/main/java/io/ebeaninternal/api/SpiTransactionProxy.java

@@ -3,6 +3,7 @@ package io.ebeaninternal.api;
 import io.ebean.ProfileLocation;
 import io.ebean.TransactionCallback;
 import io.ebean.annotation.DocStoreMode;
+import io.ebean.bean.FrozenBeans;
 import io.ebean.event.changelog.BeanChange;
 import io.ebean.event.changelog.ChangeSet;
 import io.ebeaninternal.server.core.PersistDeferredRelationship;
@@ -223,6 +224,16 @@ public abstract class SpiTransactionProxy implements SpiTransaction {
     transaction.register(callback);
   }
 
+  @Override
+  public FrozenBeans freezeAndDetach() {
+    return transaction.freezeAndDetach();
+  }
+
+  @Override
+  public void attach(FrozenBeans frozenBeans) {
+    transaction.attach(frozenBeans);
+  }
+
   @Override
   public boolean isReadOnly() {
     return transaction.isReadOnly();

ebean-core/src/main/java/io/ebeaninternal/json/ModifyAwareFlag.java

@@ -23,4 +23,8 @@ public final class ModifyAwareFlag implements ModifyAwareType, Serializable {
     this.markedDirty = markedDirty;
   }
 
+  @Override
+  public Object freeze() {
+    throw new UnsupportedOperationException();
+  }
 }

ebean-core/src/main/java/io/ebeaninternal/json/ModifyAwareList.java

@@ -3,12 +3,7 @@ package io.ebeaninternal.json;
 import io.ebean.ModifyAwareType;
 
 import java.io.Serializable;
-import java.util.Collection;
-import java.util.Iterator;
-import java.util.LinkedHashSet;
-import java.util.List;
-import java.util.ListIterator;
-import java.util.Objects;
+import java.util.*;
 
 /**
  * Modify aware wrapper of a list.
@@ -52,6 +47,11 @@ public final class ModifyAwareList<E> implements List<E>, ModifyAwareType, Seria
     return list.hashCode();
   }
 
+  @Override
+  public List<E> freeze() {
+    return Collections.unmodifiableList(list);
+  }
+
   @Override
   public boolean isMarkedDirty() {
     return owner.isMarkedDirty();

ebean-core/src/main/java/io/ebeaninternal/json/ModifyAwareMap.java

@@ -3,11 +3,7 @@ package io.ebeaninternal.json;
 import io.ebean.ModifyAwareType;
 
 import java.io.Serializable;
-import java.util.Collection;
-import java.util.LinkedHashSet;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Set;
+import java.util.*;
 
 /**
  * Map that is wraps an underlying map for the purpose of detecting changes.
@@ -51,6 +47,11 @@ public final class ModifyAwareMap<K, V> implements Map<K, V>, ModifyAwareType, S
     return map.hashCode();
   }
 
+  @Override
+  public Map<K, V> freeze() {
+    return Collections.unmodifiableMap(map);
+  }
+
   @Override
   public boolean isMarkedDirty() {
     return owner.isMarkedDirty();

ebean-core/src/main/java/io/ebeaninternal/json/ModifyAwareSet.java

@@ -3,10 +3,7 @@ package io.ebeaninternal.json;
 import io.ebean.ModifyAwareType;
 
 import java.io.Serializable;
-import java.util.Collection;
-import java.util.Iterator;
-import java.util.Objects;
-import java.util.Set;
+import java.util.*;
 
 /**
  * Wraps a Set for the purposes of detecting modifications.
@@ -33,6 +30,11 @@ public final class ModifyAwareSet<E> implements Set<E>, ModifyAwareType, Seriali
     this.set = underlying;
   }
 
+  @Override
+  public Set<E> freeze() {
+    return Collections.unmodifiableSet(set);
+  }
+
   @Override
   public boolean isMarkedDirty() {
     return owner.isMarkedDirty();

ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanDescriptor.java

@@ -687,6 +687,16 @@ public class BeanDescriptor<T> implements BeanType<T>, STreeType, SpiBeanType {
     }
   }
 
+  public void freeze(EntityBean entityBean) {
+    for (BeanProperty beanProperty : propertiesMutable) {
+      beanProperty.freeze(entityBean);
+    }
+    for (BeanPropertyAssocMany<?> many : propertiesMany) {
+      many.freeze(entityBean);
+    }
+    entityBean._ebean_getIntercept().freeze();
+  }
+
   public void metricPersistBatch(PersistRequest.Type type, long startNanos, int size) {
     iudMetrics.addBatch(type, startNanos, size);
   }

ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanProperty.java

@@ -1,11 +1,9 @@
 package io.ebeaninternal.server.deploy;
 
 import com.fasterxml.jackson.core.JsonToken;
+import io.ebean.ModifyAwareType;
 import io.ebean.ValuePair;
-import io.ebean.bean.EntityBean;
-import io.ebean.bean.EntityBeanIntercept;
-import io.ebean.bean.MutableValueInfo;
-import io.ebean.bean.PersistenceContext;
+import io.ebean.bean.*;
 import io.ebean.config.EncryptKey;
 import io.ebean.config.dbplatform.DbEncryptFunction;
 import io.ebean.config.dbplatform.DbPlatformType;
@@ -1498,4 +1496,15 @@ public class BeanProperty implements ElPropertyValue, Property, STreeProperty {
       desc.registerColumn(dbColumn, path);
     }
   }
+
+  /**
+   * Freeze mutable types (like DbArray).
+   */
+  public void freeze(EntityBean entityBean) {
+    Object value = getValue(entityBean);
+    if (value instanceof ModifyAwareType) {
+      ModifyAwareType bc = (ModifyAwareType) value;
+      setValue(entityBean, bc.freeze());
+    }
+  }
 }

ebean-core/src/main/java/io/ebeaninternal/server/deploy/BeanPropertyAssocMany.java

@@ -1133,4 +1133,13 @@ public class BeanPropertyAssocMany<T> extends BeanPropertyAssoc<T> implements ST
       return false;
     }
   }
+
+  @Override
+  public void freeze(EntityBean entityBean) {
+    Object value = getValue(entityBean);
+    if (value instanceof BeanCollection) {
+      BeanCollection<?> bc = (BeanCollection<?>) value;
+      setValue(entityBean, bc.freeze());
+    }
+  }
 }

ebean-core/src/main/java/io/ebeaninternal/server/query/SqlTreeLoadBean.java

@@ -31,7 +31,7 @@ class SqlTreeLoadBean implements SqlTreeLoad {
   final boolean readId;
   private final boolean readIdNormal;
   private final boolean disableLazyLoad;
-  private final boolean readOnlyNoIntercept;
+  private final boolean readOnly;
   private final InheritInfo inheritInfo;
   final String prefix;
   private final Map<String, String> pathMap;
@@ -54,7 +54,7 @@ class SqlTreeLoadBean implements SqlTreeLoad {
     this.readId = node.readId;
     this.readIdNormal = readId && !temporalVersions;
     this.disableLazyLoad = node.disableLazyLoad;
-    this.readOnlyNoIntercept = disableLazyLoad && node.readOnly;
+    this.readOnly = node.readOnly;
     this.partialObject = node.partialObject;
     this.properties = node.properties;
     this.pathMap = node.pathMap;
@@ -162,7 +162,7 @@ class SqlTreeLoadBean implements SqlTreeLoad {
 
     void initBeanType() throws SQLException {
       localDesc = desc;
-      localBean = desc.createEntityBean2(readOnlyNoIntercept);
+      localBean = desc.createEntityBean2(readOnly);
       localIdBinder = idBinder;
     }
 
@@ -302,7 +302,7 @@ class SqlTreeLoadBean implements SqlTreeLoad {
       boolean forceNewReference = queryMode == Mode.REFRESH_BEAN;
       for (STreePropertyAssocMany many : localDesc.propsMany()) {
         if (many != loadingChildProperty) {
-          if (readOnlyNoIntercept) {
+          if (disableLazyLoad && readOnly) {
             many.createEmptyReference(localBean);
           } else {
             // create a proxy for the many (deferred fetching)

ebean-core/src/main/java/io/ebeaninternal/server/transaction/DFrozenBeans.java

@@ -0,0 +1,23 @@
+package io.ebeaninternal.server.transaction;
+
+import io.ebean.bean.FrozenBeans;
+import io.ebean.bean.EntityBean;
+
+import java.util.Collections;
+import java.util.Map;
+import java.util.Set;
+
+final class DFrozenBeans implements FrozenBeans {
+
+  private static final long serialVersionUID = 1L;
+
+  private final Map<Class<?>, Map<Object, EntityBean>> beans;
+
+  DFrozenBeans(Map<Class<?>, Map<Object, EntityBean>> beans) {
+    this.beans = Collections.unmodifiableMap(beans);
+  }
+
+  Set<Map.Entry<Class<?>, Map<Object, EntityBean>>> entries() {
+    return beans.entrySet();
+  }
+}

ebean-core/src/main/java/io/ebeaninternal/server/transaction/DefaultPersistenceContext.java

@@ -1,5 +1,6 @@
 package io.ebeaninternal.server.transaction;
 
+import io.ebean.bean.FrozenBeans;
 import io.ebean.bean.EntityBean;
 import io.ebeaninternal.api.SpiBeanType;
 import io.ebeaninternal.api.SpiBeanTypeManager;
@@ -44,6 +45,33 @@ public final class DefaultPersistenceContext implements SpiPersistenceContext {
   public DefaultPersistenceContext() {
   }
 
+  public void attach(FrozenBeans other) {
+    lock.lock();
+    try {
+      DFrozenBeans otherContext = (DFrozenBeans) other;
+      for (Map.Entry<Class<?>, Map<Object, EntityBean>> entry : otherContext.entries()) {
+        classContext(entry.getKey()).attach(entry.getValue());
+      }
+    } finally {
+      lock.unlock();
+    }
+  }
+
+  @Override
+  public Map<Class<?>, List<EntityBean>> detach() {
+    lock.lock();
+    try {
+      expungeStaleEntries();
+      Map<Class<?>, List<EntityBean>> result = new LinkedHashMap<>();
+      for (Map.Entry<Class<?>, ClassContext> entry : typeCache.entrySet()) {
+        result.put(entry.getKey(), entry.getValue().beans());
+      }
+      return result;
+    } finally {
+      lock.unlock();
+    }
+  }
+
   @Override
   public void beginIterate() {
     lock.lock();
@@ -247,6 +275,23 @@ public final class DefaultPersistenceContext implements SpiPersistenceContext {
       return "size:" + map.size() + " (" + weakCount + " weak)";
     }
 
+    List<EntityBean> beans() {
+      List<EntityBean> beans = new ArrayList<>(map.size());
+      for (Object value : map.values()) {
+        if (value instanceof BeanRef) {
+          value = ((BeanRef) value).get();
+        }
+        if (value != null) {
+          beans.add((EntityBean) value);
+        }
+      }
+      return beans;
+    }
+
+    void attach(Map<Object, EntityBean> value) {
+      map.putAll(value);
+    }
+
     private Object get(Object id) {
       Object ret = map.get(id);
       if (ret instanceof BeanRef) {

ebean-core/src/main/java/io/ebeaninternal/server/transaction/JdbcTransaction.java

@@ -3,6 +3,7 @@ package io.ebeaninternal.server.transaction;
 import io.ebean.ProfileLocation;
 import io.ebean.TransactionCallback;
 import io.ebean.annotation.DocStoreMode;
+import io.ebean.bean.FrozenBeans;
 import io.ebean.config.DatabaseConfig;
 import io.ebean.event.changelog.BeanChange;
 import io.ebean.event.changelog.ChangeSet;
@@ -130,6 +131,16 @@ class JdbcTransaction implements SpiTransaction, TxnProfileEventCodes {
     }
   }
 
+  @Override
+  public FrozenBeans freezeAndDetach() {
+    return manager.freezeAndDetach(persistenceContext);
+  }
+
+  @Override
+  public void attach(FrozenBeans frozenBeans) {
+    persistenceContext.attach(frozenBeans);
+  }
+
   @Override
   public final void setLabel(String label) {
     this.label = label;

ebean-core/src/main/java/io/ebeaninternal/server/transaction/TransactionManager.java

@@ -6,6 +6,8 @@ import io.ebean.ProfileLocation;
 import io.ebean.TxScope;
 import io.ebean.annotation.PersistBatch;
 import io.ebean.annotation.TxType;
+import io.ebean.bean.FrozenBeans;
+import io.ebean.bean.EntityBean;
 import io.ebean.cache.ServerCacheNotification;
 import io.ebean.cache.ServerCacheNotify;
 import io.ebean.config.CurrentTenantProvider;
@@ -22,6 +24,7 @@ import io.ebeaninternal.api.*;
 import io.ebeaninternal.api.TransactionEventTable.TableIUD;
 import io.ebeaninternal.server.cache.CacheChangeSet;
 import io.ebeaninternal.server.cluster.ClusterManager;
+import io.ebeaninternal.server.deploy.BeanDescriptor;
 import io.ebeaninternal.server.deploy.BeanDescriptorManager;
 import io.ebeaninternal.server.profile.TimedProfileLocation;
 import io.ebeaninternal.server.profile.TimedProfileLocationRegistry;
@@ -33,7 +36,9 @@ import jakarta.persistence.PersistenceException;
 import javax.sql.DataSource;
 import java.sql.Connection;
 import java.sql.SQLException;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
@@ -637,4 +642,21 @@ public class TransactionManager implements SpiTransactionManager {
     }
   }
 
+  public FrozenBeans freezeAndDetach(SpiPersistenceContext persistenceContext) {
+    Map<Class<?>, Map<Object, EntityBean>> allBeans = new HashMap<>();
+    for (Map.Entry<Class<?>, List<EntityBean>> entry : persistenceContext.detach().entrySet()) {
+      allBeans.put(entry.getKey(), freezeBeanMap(entry));
+    }
+    return new DFrozenBeans(allBeans);
+  }
+
+  private Map<Object, EntityBean> freezeBeanMap(Map.Entry<Class<?>, List<EntityBean>> entry) {
+    BeanDescriptor<?> descriptor = beanDescriptorManager.descriptor(entry.getKey());
+    Map<Object, EntityBean> beanMap = new HashMap<>();
+    for (EntityBean entityBean : entry.getValue()) {
+      descriptor.freeze(entityBean);
+      beanMap.put(descriptor.getId(entityBean), entityBean);
+    }
+    return beanMap;
+  }
 }

ebean-core/src/main/java/io/ebeaninternal/server/type/ModifyAwareType.java

@@ -1,6 +0,0 @@
-package io.ebeaninternal.server.type;
-
-public interface ModifyAwareType {
-
-  boolean isDirty();
-}

ebean-test/src/test/java/org/tests/model/json/PlainBeanDirtyAware.java

@@ -35,6 +35,11 @@ public class PlainBeanDirtyAware implements ModifyAwareType {
     return markedDirty;
   }
 
+  @Override
+  public Object freeze() {
+    return this;
+  }
+
   @Override
   public void setMarkedDirty(boolean markedDirty) {
     this.markedDirty = markedDirty;

ebean-test/src/test/java/org/tests/query/TestQueryOrderById.java

@@ -1,5 +1,7 @@
 package org.tests.query;
 
+import io.ebean.Transaction;
+import io.ebean.bean.FrozenBeans;
 import io.ebean.bean.EntityBean;
 import io.ebean.bean.EntityBeanIntercept;
 import io.ebean.bean.InterceptReadOnly;
@@ -7,23 +9,145 @@ import io.ebean.xtest.BaseTestCase;
 import io.ebean.DB;
 import io.ebean.Query;
 import org.junit.jupiter.api.Test;
-import org.tests.model.basic.Customer;
-import org.tests.model.basic.ResetBasicData;
+import org.tests.model.basic.*;
 
+import java.io.*;
 import java.util.Collections;
 import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
 public class TestQueryOrderById extends BaseTestCase {
 
+
+  private Set<Integer> cachedCustomerIds;
+
+  @Test
+  void cachedBeanContext_attach() {
+    ResetBasicData.reset();
+
+    FrozenBeans cachedBeanContext = testSerialiseCachedBeans(buildCachedBeans());
+
+    testSerialiseCustomer(cachedCustomers.get(0));
+
+    try (Transaction txn = DB.beginTransaction()) {
+
+      txn.attach(cachedBeanContext);
+
+      List<Order> orders = DB.find(Order.class)
+        .findList();
+
+      for (Order order : orders) {
+        Customer customer = order.getCustomer();
+        if (cachedCustomerIds.contains(customer.getId())) {
+          List<Order> orders1 = customer.getOrders();
+          assertThat(orders1).isEmpty();
+          assertThat(orders1).isSameAs(Collections.EMPTY_LIST);
+
+          // customer.setContacts(new ArrayList<>());
+          // customer.setName("modified");
+          Address billingAddress = customer.getBillingAddress();
+          if (billingAddress != null) {
+            String line1 = billingAddress.getLine1();
+            Country country = billingAddress.getCountry();
+          }
+          Address shippingAddress = customer.getShippingAddress();
+//          if (shippingAddress != null) {
+//            // shippingAddress.getCountry();
+//          }
+        }
+      }
+    }
+  }
+
+  private static FrozenBeans testSerialiseCachedBeans(FrozenBeans source) {
+    try {
+      ByteArrayOutputStream os = new ByteArrayOutputStream();
+      ObjectOutputStream oos = new ObjectOutputStream(os);
+      oos.writeObject(source);
+      oos.close();
+
+      byte[] byteArray = os.toByteArray();
+
+      var is = new ByteArrayInputStream(byteArray);
+      ObjectInputStream ois = new ObjectInputStream(is);
+      FrozenBeans result = (FrozenBeans)ois.readObject();
+      assertThat(result).isNotNull();
+
+      return result;
+
+    } catch (Exception e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  private static void testSerialiseCustomer(Customer source) {
+    try {
+      ByteArrayOutputStream os = new ByteArrayOutputStream();
+      ObjectOutputStream oos = new ObjectOutputStream(os);
+      oos.writeObject(source);
+      oos.close();
+
+      byte[] byteArray = os.toByteArray();
+
+      var is = new ByteArrayInputStream(byteArray);
+      ObjectInputStream ois = new ObjectInputStream(is);
+      Customer customer = (Customer)ois.readObject();
+
+      assertThat(customer.getId()).isEqualTo(source.getId());
+      assertThat(customer.getName()).isEqualTo(source.getName());
+
+    } catch (Exception e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  private List<Customer> cachedCustomers;
+
+  private FrozenBeans buildCachedBeans() {
+    try (Transaction txn = DB.beginTransaction()) {
+
+      List<Customer> list = DB.find(Customer.class)
+        .setReadOnly(true)
+        //.setDisableLazyLoading(true)
+        .orderBy("id")
+        .setMaxRows(3)
+        .findList();
+
+      // perform some lazy loading if we desire
+      for (Customer customer : list) {
+        Address billingAddress = customer.getBillingAddress();
+        if (billingAddress != null) {
+          Country country = billingAddress.getCountry();
+          if (country != null) {
+            country.getName();
+          }
+        }
+      }
+
+      // can selectively use DisableLazyLoad which is "lazy loading is NO-operation"
+      //for (Customer customer : list) {
+      //  DB.beanState(customer).setDisableLazyLoad(true);
+      //}
+
+      cachedCustomerIds = list.stream()
+        .map(BasicDomain::getId)
+        .collect(Collectors.toSet());
+
+      cachedCustomers = list;
+      return txn.freezeAndDetach();
+    }
+  }
+
   @Test
   public void orderById_default_expectNotOrderById() {
     ResetBasicData.reset();
 
     Query<Customer> query = DB.find(Customer.class)
       .select("id,name")
-      .order("id")
+      .orderBy("id")
       .setFirstRow(1)
       .setMaxRows(5);