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Merged
chaokunyang merged 2 commits into from
Apr 28, 2026
Merged

fix(java): preserve externalizable containers in compatible mode #3628

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dbe58fe
test(java): reproduce compatible externalizable map loss
mandrean Apr 28, 2026
39ef80e
fix(java): preserve externalizable containers in compatible mode
mandrean Apr 28, 2026
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8 changes: 6 additions & 2 deletions java/fory-core/src/main/java/org/apache/fory/resolver/ClassResolver.java
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Original file line number Diff line number Diff line change
Expand Up @@ -1350,7 +1350,9 @@ public Class<? extends Serializer> getSerializerClass(Class<?> cls, boolean code
if (serializerClass != null) {
return serializerClass;
}
if (requireJavaSerialization(cls) || useReplaceResolveSerializer(cls)) {
if (Externalizable.class.isAssignableFrom(cls)
|| requireJavaSerialization(cls)
|| useReplaceResolveSerializer(cls)) {
return CollectionSerializers.JDKCompatibleCollectionSerializer.class;
}
if (!isCrossLanguage()) {
Expand All @@ -1364,7 +1366,9 @@ public Class<? extends Serializer> getSerializerClass(Class<?> cls, boolean code
if (serializerClass != null) {
return serializerClass;
}
if (requireJavaSerialization(cls) || useReplaceResolveSerializer(cls)) {
if (Externalizable.class.isAssignableFrom(cls)
|| requireJavaSerialization(cls)
|| useReplaceResolveSerializer(cls)) {
return MapSerializers.JDKCompatibleMapSerializer.class;
}
if (!isCrossLanguage()) {
Expand Down
6 changes: 5 additions & 1 deletion .../fory-core/src/main/java/org/apache/fory/serializer/collection/CollectionSerializers.java
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@

package org.apache.fory.serializer.collection;

import java.io.Externalizable;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.reflect.Field;
Expand Down Expand Up @@ -60,6 +61,7 @@
import org.apache.fory.resolver.TypeInfo;
import org.apache.fory.resolver.TypeInfoHolder;
import org.apache.fory.resolver.TypeResolver;
import org.apache.fory.serializer.ExternalizableSerializer;
import org.apache.fory.serializer.ReplaceResolveSerializer;
import org.apache.fory.serializer.Serializer;
import org.apache.fory.serializer.Serializers;
Expand Down Expand Up @@ -949,7 +951,9 @@ public JDKCompatibleCollectionSerializer(TypeResolver typeResolver, Class<T> cls
Class<? extends Serializer> serializerType =
ClassResolver.useReplaceResolveSerializer(cls)
? ReplaceResolveSerializer.class
: config.getDefaultJDKStreamSerializerType();
: Externalizable.class.isAssignableFrom(cls)
? ExternalizableSerializer.class
: config.getDefaultJDKStreamSerializerType();
serializer = Serializers.newSerializer(typeResolver, cls, serializerType);
}

Expand Down
6 changes: 5 additions & 1 deletion java/fory-core/src/main/java/org/apache/fory/serializer/collection/MapSerializers.java
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@

package org.apache.fory.serializer.collection;

import java.io.Externalizable;
import java.lang.invoke.MethodHandle;
import java.util.Collection;
import java.util.Collections;
Expand All @@ -43,6 +44,7 @@
import org.apache.fory.resolver.ClassResolver;
import org.apache.fory.resolver.TypeInfo;
import org.apache.fory.resolver.TypeResolver;
import org.apache.fory.serializer.ExternalizableSerializer;
import org.apache.fory.serializer.ReplaceResolveSerializer;
import org.apache.fory.serializer.Serializer;
import org.apache.fory.serializer.Serializers;
Expand Down Expand Up @@ -459,7 +461,9 @@ public JDKCompatibleMapSerializer(TypeResolver typeResolver, Class<T> cls) {
Class<? extends Serializer> serializerType =
ClassResolver.useReplaceResolveSerializer(cls)
? ReplaceResolveSerializer.class
: config.getDefaultJDKStreamSerializerType();
: Externalizable.class.isAssignableFrom(cls)
? ExternalizableSerializer.class
: config.getDefaultJDKStreamSerializerType();
serializer = Serializers.newSerializer(typeResolver, cls, serializerType);
}

Expand Down
61 changes: 61 additions & 0 deletions java/fory-core/src/test/java/org/apache/fory/serializer/collection/MapSerializersTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,10 @@
import static org.testng.Assert.assertEquals;

import com.google.common.collect.ImmutableMap;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.Serializable;
import java.util.AbstractMap;
import java.util.ArrayList;
Expand Down Expand Up @@ -832,6 +836,63 @@ public Object put(String key, Object value) {
}
}

public static class ExternalizableStringMap extends AbstractMap<String, String>
implements Externalizable {
private transient Map<String, String> data = new LinkedHashMap<>();

public ExternalizableStringMap() {}

@Override
public Set<Map.Entry<String, String>> entrySet() {
return data.entrySet();
}

@Override
public String put(String key, String value) {
return data.put(key, value);
}

@Override
public void writeExternal(ObjectOutput out) throws IOException {
out.writeInt(size());
for (Map.Entry<String, String> entry : entrySet()) {
out.writeObject(entry.getKey());
out.writeObject(entry.getValue());
}
}

@Override
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
data = new LinkedHashMap<>();
int size = in.readInt();
for (int i = 0; i < size; i++) {
put((String) in.readObject(), (String) in.readObject());
}
}
}

public static class ExternalizableMapHolder {
public Map<String, String> data = new ExternalizableStringMap();
}

@Test(dataProvider = "enableCodegen")
public void testExternalizableMapCompatibleMode(boolean enableCodegen) {
Fory fory =
builder()
.withLanguage(Language.JAVA)
.withCompatibleMode(CompatibleMode.COMPATIBLE)
.withCodegen(enableCodegen)
.requireClassRegistration(false)
.build();
ExternalizableMapHolder holder = new ExternalizableMapHolder();
holder.data.put("k", "v");

ExternalizableMapHolder deserialized = serDe(fory, holder);
Assert.assertEquals(deserialized.data.getClass(), ExternalizableStringMap.class);
Assert.assertEquals(deserialized.data, holder.data);
Assert.assertEquals(deserialized.data.get("k"), "v");
}

@Test(dataProvider = "enableCodegen")
public void testDefaultMapSerializer(boolean enableCodegen) {
Fory fory =
Expand Down
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