Custom Logger serializer and its related unit-test.

Custom Logger serialiser using only its name when serialising and deserialising using LoggerFactory.getLogger(name).

core/src/main/kotlin/net/corda/core/serialization/DefaultKryoCustomizer.kt

@@ -17,6 +17,7 @@ import net.corda.core.utilities.NonEmptySetSerializer
 import net.i2p.crypto.eddsa.EdDSAPrivateKey
 import net.i2p.crypto.eddsa.EdDSAPublicKey
 import org.objenesis.strategy.StdInstantiatorStrategy
+import org.slf4j.Logger
 import java.io.BufferedInputStream
 import java.util.*
 
@@ -34,7 +35,7 @@ object DefaultKryoCustomizer {
             // for change to a class.
             setDefaultSerializer(CompatibleFieldSerializer::class.java)
             // Take the safest route here and allow subclasses to have fields named the same as super classes.
-            fieldSerializerConfig.setCachedFieldNameStrategy(FieldSerializer.CachedFieldNameStrategy.EXTENDED)
+            fieldSerializerConfig.cachedFieldNameStrategy = FieldSerializer.CachedFieldNameStrategy.EXTENDED
 
             // Allow construction of objects using a JVM backdoor that skips invoking the constructors, if there is no
             // no-arg constructor available.
@@ -78,6 +79,8 @@ object DefaultKryoCustomizer {
             register(MetaData::class.java, MetaDataSerializer)
             register(BitSet::class.java, ReferencesAwareJavaSerializer)
 
+            addDefaultSerializer(Logger::class.java, LoggerSerializer)
+
             val customization = KryoSerializationCustomization(this)
             pluginRegistries.forEach { it.customizeSerialization(customization) }
         }

core/src/main/kotlin/net/corda/core/serialization/Kryo.kt

@@ -5,7 +5,6 @@ import com.esotericsoftware.kryo.io.Input
 import com.esotericsoftware.kryo.io.Output
 import com.esotericsoftware.kryo.pool.KryoPool
 import com.esotericsoftware.kryo.serializers.JavaSerializer
-import com.esotericsoftware.kryo.serializers.MapSerializer
 import com.esotericsoftware.kryo.util.MapReferenceResolver
 import com.google.common.annotations.VisibleForTesting
 import net.corda.core.contracts.*
@@ -17,6 +16,8 @@ import net.i2p.crypto.eddsa.EdDSAPrivateKey
 import net.i2p.crypto.eddsa.EdDSAPublicKey
 import net.i2p.crypto.eddsa.spec.EdDSAPrivateKeySpec
 import net.i2p.crypto.eddsa.spec.EdDSAPublicKeySpec
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
 import java.io.*
 import java.lang.reflect.InvocationTargetException
 import java.nio.file.Files
@@ -579,3 +580,15 @@ object MetaDataSerializer : Serializer<MetaData>() {
         return MetaData(schemeCodeName, versionID, signatureType, timestamp, visibleInputs, signedInputs, merkleRoot, publicKey)
     }
 }
+
+/** For serialising a Logger. */
+@ThreadSafe
+object LoggerSerializer : Serializer<Logger>() {
+    override fun write(kryo: Kryo, output: Output, obj: Logger) {
+        output.writeString(obj.name)
+    }
+
+    override fun read(kryo: Kryo, input: Input, type: Class<Logger>): Logger {
+        return LoggerFactory.getLogger(input.readString())
+    }
+}

core/src/test/kotlin/net/corda/core/serialization/KryoTests.kt

@@ -11,11 +11,13 @@ import org.bouncycastle.pqc.jcajce.provider.BouncyCastlePQCProvider
 import org.junit.After
 import org.junit.Before
 import org.junit.Test
+import org.slf4j.LoggerFactory
 import java.io.InputStream
 import java.security.Security
 import java.time.Instant
 import java.util.*
 import kotlin.test.assertEquals
+import kotlin.test.assertTrue
 
 class KryoTests {
 
@@ -125,6 +127,14 @@ class KryoTests {
         assertEquals(meta2, meta)
     }
 
+    @Test
+    fun `serialize - deserialize Logger`() {
+        val logger = LoggerFactory.getLogger("aName")
+        val logger2 = logger.serialize(storageKryo()).deserialize(storageKryo())
+        assertEquals(logger.name, logger2.name)
+        assertTrue(logger === logger2)
+    }
+
     @CordaSerializable
     private data class Person(val name: String, val birthday: Instant?)