HashBiMap SerializationException or how to seriali

Question

Problem seems to be that not all Guava classes are serializable out-of-the-box.

I found a quite good solution to this and like to share it. (in this case for HashBiMap). (Maybe some Guava developers may apply this one day to ideally all of the classes)

If you copy the below class (and maybe adjust it to your to-be-serializable class) you will have further investigation details inside the Javadoc comment already.

package com.google.common.collect;

import java.util.LinkedHashMap;
import java.util.Map;

import com.google.gwt.user.client.rpc.SerializationException;
import com.google.gwt.user.client.rpc.SerializationStreamReader;
import com.google.gwt.user.client.rpc.SerializationStreamWriter;
import com.google.gwt.user.client.rpc.core.java.util.Map_CustomFieldSerializerBase;

/**
 * idea taken from some <a href=
 * "http://code.google.com/r/baggiogamp-guava/source/browse/gwt-src/com/google/common/collect/RegularImmutableBiMap_CustomFieldSerializer.java?r=a7aa10ddb815ce7996f3fae103bfd3823b1336ed&spec=svn6923b5fac0feb7005429d0b24be93b91685f9637"
 * >com/google/common/collect/RegularImmutableBiMap_CustomFieldSerializer.java</
 * a> <br/>
 * Problem was, that {@link HashBiMap} seems not to be serializable for GWT:
 * <ul>
 * <li>it nor its super classes do not implement com.google.gwt.user.client.rpc.IsSerializable (why?)</li>
 * <li>the following solution does not work if only applied to some super class, e.g. AbstractBiMap</li>
 * </ul>
 * <pre>
 * com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException: The response could not be deserialized
    at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:221)
    at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287)
    at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395)
    at sun.reflect.GeneratedMethodAccessor119.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:338)
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:219)
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:571)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:279)
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
    at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
    at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:242)
    at sun.reflect.GeneratedMethodAccessor116.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:293)
    at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:547)
    at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:364)
    at java.lang.Thread.run(Unknown Source)
Caused by: com.google.gwt.user.client.rpc.SerializationException: com.google.common.collect.HashBiMap/1352983899
    at com.google.gwt.user.client.rpc.impl.SerializerBase.getTypeHandler(SerializerBase.java:153)
    at com.google.gwt.user.client.rpc.impl.SerializerBase.instantiate(SerializerBase.java:114)
    at com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader.deserialize(ClientSerializationStreamReader.java:396)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader.readObject(AbstractSerializationStreamReader.java:119)
    at mycomp.shared.conf.Config_FieldSerializer.deserialize(Config_FieldSerializer.java:12)
    at mycomp.shared.conf.Config_FieldSerializer.deserial(Config_FieldSerializer.java:35)
    at com.google.gwt.user.client.rpc.impl.SerializerBase.deserialize(SerializerBase.java:95)
    at com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader.deserialize(ClientSerializationStreamReader.java:398)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader.readObject(AbstractSerializationStreamReader.java:119)
    at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter$ResponseReader$8.read(RequestCallbackAdapter.java:106)
    at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:214)
    at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287)
    at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395)
    at sun.reflect.GeneratedMethodAccessor119.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:338)
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:219)
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:571)
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:279)
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
    at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
    at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:242)
    at sun.reflect.GeneratedMethodAccessor116.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:172)
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:293)
    at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:547)
    at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:364)
    at java.lang.Thread.run(Unknown Source)
 * </pre>
 * 
 * @author ADietrich
 * 
 */
public class HashBiMap_CustomFieldSerializer {

    public static void deserialize(SerializationStreamReader reader,
        HashBiMap<?, ?> instance) {
    }

    public static HashBiMap<Object, Object> instantiate(
            SerializationStreamReader reader) throws SerializationException {
        Map<Object, Object> entries = new LinkedHashMap<Object, Object>();
        Map_CustomFieldSerializerBase.deserialize(reader, entries);
        return HashBiMap.create(entries);
    }

    public static void serialize(SerializationStreamWriter writer,
        HashBiMap<?, ?> instance) throws SerializationException {
        Map_CustomFieldSerializerBase.serialize(writer, instance);
        }
}

Answer 1

Implementing Serializable is sufficient only for specially designed classes. Guava's classes aren't designed that way (for various reasons). As a result, we need to add special support for each individual class. We've done this for some classes, and we can do it for others, though there are tradeoffs. We have a feature request for GWT serialization where you can read more detail and make requests. However, I'd first consider using ImmutableBiMap, rather than HashBiMap, in your RPC interface. ImmutableBiMap, like most of the immutable types, is already GWT serializable.