From 910b7826ddbabaa4c2a36a657d10b35a049e0ec5 Mon Sep 17 00:00:00 2001
From: Enes Ozcan <enes.ozcan@hazelcast.com>
Date: Wed, 5 Aug 2020 13:16:17 +0300
Subject: [PATCH 1/7] Add serializer.

---
 .../hazelcast/HazelcastSessionSerializer.java | 87 +++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java

diff --git a/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java b/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
new file mode 100644
index 000000000..ec785f0c4
--- /dev/null
+++ b/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
@@ -0,0 +1,87 @@
+package org.springframework.session.hazelcast;
+
+import com.hazelcast.nio.ObjectDataInput;
+import com.hazelcast.nio.ObjectDataOutput;
+import com.hazelcast.nio.serialization.StreamSerializer;
+import org.springframework.session.MapSession;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.time.Duration;
+import java.time.Instant;
+
+public class HazelcastSessionSerializer implements StreamSerializer<MapSession> {
+
+	private static final int SERIALIZER_TYPE_ID = 12345;
+
+	@Override
+	public void write(ObjectDataOutput out, MapSession session) throws IOException {
+		out.writeUTF(session.getOriginalId());
+		out.writeUTF(session.getId());
+		writeInstant(out, session.getCreationTime());
+		writeInstant(out, session.getLastAccessedTime());
+		writeDuration(out, session.getMaxInactiveInterval());
+		for (String attrName : session.getAttributeNames()) {
+			Object attrValue = session.getAttribute(attrName);
+			if (attrValue != null) {
+				out.writeUTF(attrName);
+				out.writeObject(attrValue);
+			}
+		}
+	}
+
+	private void writeInstant(ObjectDataOutput out, Instant instant) throws IOException {
+		out.writeLong(instant.getEpochSecond());
+		out.writeInt(instant.getNano());
+	}
+
+	private void writeDuration(ObjectDataOutput out, Duration duration) throws IOException {
+		out.writeLong(duration.getSeconds());
+		out.writeInt(duration.getNano());
+	}
+
+	@Override
+	public MapSession read(ObjectDataInput in) throws IOException {
+		String originalId = in.readUTF();
+		MapSession cached = new MapSession(originalId);
+		cached.setId(in.readUTF());
+		cached.setCreationTime(readInstant(in));
+		cached.setLastAccessedTime(readInstant(in));
+		cached.setMaxInactiveInterval(readDuration(in));
+		try {
+			while (true) {
+				// During write, it's not possible to write
+				// number of non-null attributes without an extra
+				// iteration. Hence the attributes are read until
+				// EOF here.
+				String attrName = in.readUTF();
+				Object attrValue = in.readObject();
+				cached.setAttribute(attrName, attrValue);
+			}
+		} catch (EOFException ignored) {
+		}
+		return cached;
+	}
+
+	private Instant readInstant(ObjectDataInput in) throws IOException {
+		long seconds = in.readLong();
+		int nanos = in.readInt();
+		return Instant.ofEpochSecond(seconds, nanos);
+	}
+
+	private Duration readDuration(ObjectDataInput in) throws IOException {
+		long seconds = in.readLong();
+		int nanos = in.readInt();
+		return Duration.ofSeconds(seconds, nanos);
+	}
+
+	@Override
+	public int getTypeId() {
+		return SERIALIZER_TYPE_ID;
+	}
+
+	@Override
+	public void destroy() {
+	}
+
+}

From 461933854dd242753458324c15db5126e6f2554b Mon Sep 17 00:00:00 2001
From: Enes Ozcan <enes.ozcan@hazelcast.com>
Date: Fri, 7 Aug 2020 12:16:07 +0300
Subject: [PATCH 2/7] Add javadoc, use new serializer for tests.

---
 .../hazelcast/HazelcastITestUtils.java        |  5 ++
 .../hazelcast/HazelcastSessionSerializer.java | 50 +++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/spring-session-hazelcast/src/integration-test/java/org/springframework/session/hazelcast/HazelcastITestUtils.java b/spring-session-hazelcast/src/integration-test/java/org/springframework/session/hazelcast/HazelcastITestUtils.java
index 00eec67b2..608de19c2 100644
--- a/spring-session-hazelcast/src/integration-test/java/org/springframework/session/hazelcast/HazelcastITestUtils.java
+++ b/spring-session-hazelcast/src/integration-test/java/org/springframework/session/hazelcast/HazelcastITestUtils.java
@@ -20,8 +20,10 @@
 import com.hazelcast.config.MapAttributeConfig;
 import com.hazelcast.config.MapIndexConfig;
 import com.hazelcast.config.NetworkConfig;
+import com.hazelcast.config.SerializerConfig;
 import com.hazelcast.core.Hazelcast;
 import com.hazelcast.core.HazelcastInstance;
+import org.springframework.session.MapSession;
 
 /**
  * Utility class for Hazelcast integration tests.
@@ -48,6 +50,9 @@ static HazelcastInstance embeddedHazelcastServer() {
 		config.getMapConfig(HazelcastIndexedSessionRepository.DEFAULT_SESSION_MAP_NAME)
 				.addMapAttributeConfig(attributeConfig).addMapIndexConfig(
 						new MapIndexConfig(HazelcastIndexedSessionRepository.PRINCIPAL_NAME_ATTRIBUTE, false));
+		SerializerConfig serializerConfig = new SerializerConfig();
+		serializerConfig.setImplementation(new HazelcastSessionSerializer()).setTypeClass(MapSession.class);
+		config.getSerializationConfig().addSerializerConfig(serializerConfig);
 		return Hazelcast.newHazelcastInstance(config);
 	}
 
diff --git a/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java b/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
index ec785f0c4..5ad6ab63b 100644
--- a/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
+++ b/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
@@ -10,6 +10,56 @@
 import java.time.Duration;
 import java.time.Instant;
 
+/**
+ * A {@link com.hazelcast.nio.serialization.Serializer} implementation that
+ * handles the (de)serialization of {@link MapSession} stored on {@link com.hazelcast.core.IMap}.
+ *
+ * The use of this serializer is optional and provides faster serialization of
+ * sessions. If not configured to be used, Hazelcast will serialize sessions
+ * via {@link java.io.Serializable} by default.
+ *
+ * If multiple instances of a Spring application is run, then all of them need to use
+ * the same serialization method. If this serializer is registered on one instance
+ * and not another one, then it will end up with HazelcastSerializationException.
+ * The same applies when clients are configured to use this serializer but not the
+ * members, and vice versa. Also note that, if a new instance is created with this
+ * serialization but the existing Hazelcast cluster contains the values not serialized
+ * by this but instead the default one, this will result in incompatibility again.
+ *
+ * <p>
+ * An example of how to register the serializer on embedded instance can be seen below:
+ *
+ * <pre class="code">
+ * Config config = new Config();
+ *
+ * // ... other configurations for Hazelcast ...
+ *
+ * SerializerConfig serializerConfig = new SerializerConfig();
+ * serializerConfig.setImplementation(new HazelcastSessionSerializer()).setTypeClass(MapSession.class);
+ * config.getSerializationConfig().addSerializerConfig(serializerConfig);
+ *
+ * HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance(config);
+ * </pre>
+ *
+ * Below is the example of how to register the serializer on client instance. Note that,
+ * to use the serializer in client/server mode, the serializer - and hence {@link MapSession},
+ * must exist on the server's classpath and must be registered via {@link com.hazelcast.config.SerializerConfig}
+ * with the configuration above for each server.
+ *
+ * <pre class="code">
+ * ClientConfig clientConfig = new ClientConfig();
+ *
+ * // ... other configurations for Hazelcast Client ...
+ *
+ * SerializerConfig serializerConfig = new SerializerConfig();
+ * serializerConfig.setImplementation(new HazelcastSessionSerializer()).setTypeClass(MapSession.class);
+ * clientConfig.getSerializationConfig().addSerializerConfig(serializerConfig);
+ *
+ * HazelcastInstance hazelcastClient = HazelcastClient.newHazelcastClient(clientConfig);
+ * </pre>
+ *
+ * @author Enes Ozcan
+ */
 public class HazelcastSessionSerializer implements StreamSerializer<MapSession> {
 
 	private static final int SERIALIZER_TYPE_ID = 12345;

From 5e7ca6dd5bdf1713fd2b2f9e6bae0aafa8e4bc73 Mon Sep 17 00:00:00 2001
From: Enes Ozcan <enes.ozcan@hazelcast.com>
Date: Fri, 7 Aug 2020 14:42:56 +0300
Subject: [PATCH 3/7] Add serializer config to docs.

---
 .../src/docs/asciidoc/guides/java-hazelcast.adoc         | 9 ++++++++-
 .../test/java/docs/http/HazelcastHttpSessionConfig.java  | 8 +++++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/spring-session-docs/src/docs/asciidoc/guides/java-hazelcast.adoc b/spring-session-docs/src/docs/asciidoc/guides/java-hazelcast.adoc
index 03727f497..b0fd7d201 100644
--- a/spring-session-docs/src/docs/asciidoc/guides/java-hazelcast.adoc
+++ b/spring-session-docs/src/docs/asciidoc/guides/java-hazelcast.adoc
@@ -97,11 +97,18 @@ The filter is in charge of replacing the `HttpSession` implementation to be back
 In this instance, Spring Session is backed by Hazelcast.
 <2> In order to support retrieval of sessions by principal name index, an appropriate `ValueExtractor` needs to be registered.
 Spring Session provides `PrincipalNameExtractor` for this purpose.
-<3> We create a `HazelcastInstance` that connects Spring Session to Hazelcast.
+<3> In order to serialize `MapSession` objects efficiently, `HazelcastSessionSerializer` needs to be registered. If this
+is not set, Hazelcast will serialize sessions using native Java serialization.
+<4> We create a `HazelcastInstance` that connects Spring Session to Hazelcast.
 By default, the application starts and connects to an embedded instance of Hazelcast.
 For more information on configuring Hazelcast, see the https://docs.hazelcast.org/docs/{hazelcast-version}/manual/html-single/index.html#hazelcast-configuration[reference documentation].
 ====
 
+NOTE: If `HazelcastSessionSerializer` is preferred, it needs to be configured for all Hazelcast cluster members before they start.
+In a Hazelcast cluster, all members should use the same serialization method for sessions. Also, if Hazelcast Client/Server topology
+is used, then both members and clients must use the same serialization method. The serializer can be registered via `ClientConfig`
+with the same `SerializerConfiguration` of members.
+
 == Servlet Container Initialization
 
 Our <<security-spring-configuration,Spring Configuration>> created a Spring bean named `springSessionRepositoryFilter` that implements `Filter`.
diff --git a/spring-session-docs/src/test/java/docs/http/HazelcastHttpSessionConfig.java b/spring-session-docs/src/test/java/docs/http/HazelcastHttpSessionConfig.java
index 3aad03149..c77bc1d32 100644
--- a/spring-session-docs/src/test/java/docs/http/HazelcastHttpSessionConfig.java
+++ b/spring-session-docs/src/test/java/docs/http/HazelcastHttpSessionConfig.java
@@ -19,12 +19,15 @@
 import com.hazelcast.config.Config;
 import com.hazelcast.config.MapAttributeConfig;
 import com.hazelcast.config.MapIndexConfig;
+import com.hazelcast.config.SerializerConfig;
 import com.hazelcast.core.Hazelcast;
 import com.hazelcast.core.HazelcastInstance;
 
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.session.MapSession;
 import org.springframework.session.hazelcast.HazelcastIndexedSessionRepository;
+import org.springframework.session.hazelcast.HazelcastSessionSerializer;
 import org.springframework.session.hazelcast.PrincipalNameExtractor;
 import org.springframework.session.hazelcast.config.annotation.web.http.EnableHazelcastHttpSession;
 
@@ -42,7 +45,10 @@ public HazelcastInstance hazelcastInstance() {
 		config.getMapConfig(HazelcastIndexedSessionRepository.DEFAULT_SESSION_MAP_NAME) // <2>
 				.addMapAttributeConfig(attributeConfig).addMapIndexConfig(
 						new MapIndexConfig(HazelcastIndexedSessionRepository.PRINCIPAL_NAME_ATTRIBUTE, false));
-		return Hazelcast.newHazelcastInstance(config); // <3>
+		SerializerConfig serializerConfig = new SerializerConfig();
+		serializerConfig.setImplementation(new HazelcastSessionSerializer()).setTypeClass(MapSession.class);
+		config.getSerializationConfig().addSerializerConfig(serializerConfig); // <3>
+		return Hazelcast.newHazelcastInstance(config); // <4>
 	}
 
 }

From c5a0bd26020dae8d039c37aa28427e6c0bbc992e Mon Sep 17 00:00:00 2001
From: Enes Ozcan <enes.ozcan@hazelcast.com>
Date: Fri, 7 Aug 2020 14:59:55 +0300
Subject: [PATCH 4/7] Use random id, fix javadoc.

---
 .../session/hazelcast/HazelcastSessionSerializer.java         | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java b/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
index 5ad6ab63b..65d9ec402 100644
--- a/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
+++ b/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
@@ -14,10 +14,12 @@
  * A {@link com.hazelcast.nio.serialization.Serializer} implementation that
  * handles the (de)serialization of {@link MapSession} stored on {@link com.hazelcast.core.IMap}.
  *
+ * <p>
  * The use of this serializer is optional and provides faster serialization of
  * sessions. If not configured to be used, Hazelcast will serialize sessions
  * via {@link java.io.Serializable} by default.
  *
+ * <p>
  * If multiple instances of a Spring application is run, then all of them need to use
  * the same serialization method. If this serializer is registered on one instance
  * and not another one, then it will end up with HazelcastSerializationException.
@@ -62,7 +64,7 @@
  */
 public class HazelcastSessionSerializer implements StreamSerializer<MapSession> {
 
-	private static final int SERIALIZER_TYPE_ID = 12345;
+	private static final int SERIALIZER_TYPE_ID = 1453;
 
 	@Override
 	public void write(ObjectDataOutput out, MapSession session) throws IOException {

From e2f5d0856a3aa77fd7bee360d9f622e8577fd227 Mon Sep 17 00:00:00 2001
From: Enes Ozcan <enes.ozcan@hazelcast.com>
Date: Fri, 7 Aug 2020 15:18:52 +0300
Subject: [PATCH 5/7] Add test.

---
 .../HazelcastSessionSerializerTest.java       | 81 +++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/HazelcastSessionSerializerTest.java

diff --git a/spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/HazelcastSessionSerializerTest.java b/spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/HazelcastSessionSerializerTest.java
new file mode 100644
index 000000000..17e749f57
--- /dev/null
+++ b/spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/HazelcastSessionSerializerTest.java
@@ -0,0 +1,81 @@
+package org.springframework.session.hazelcast;
+
+import com.hazelcast.config.SerializationConfig;
+import com.hazelcast.config.SerializerConfig;
+import com.hazelcast.internal.serialization.impl.DefaultSerializationServiceBuilder;
+import com.hazelcast.nio.serialization.Data;
+import com.hazelcast.spi.serialization.SerializationService;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.session.MapSession;
+
+import java.io.Serializable;
+import java.time.Duration;
+import java.time.Instant;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class HazelcastSessionSerializerTests {
+
+	private SerializationService serializationService;
+
+	@BeforeEach
+	void setUp() {
+		SerializationConfig serializationConfig = new SerializationConfig();
+		SerializerConfig serializerConfig = new SerializerConfig()
+				.setImplementation(new HazelcastSessionSerializer())
+				.setTypeClass(MapSession.class);
+		serializationConfig.addSerializerConfig(serializerConfig);
+		serializationService = new DefaultSerializationServiceBuilder().setConfig(serializationConfig).build();
+	}
+
+	@Test
+	void serializeSessionWithStreamSerializer() {
+		MapSession originalSession = new MapSession();
+		originalSession.setAttribute("attr1", "value1");
+		originalSession.setAttribute("attr2", "value2");
+		originalSession.setAttribute("attr3", new SerializableTestAttribute(3));
+		originalSession.setMaxInactiveInterval(Duration.ofDays(5));
+		originalSession.setLastAccessedTime(Instant.now());
+		originalSession.setId("custom-id");
+
+		Data serialized = serializationService.toData(originalSession);
+		MapSession cached = serializationService.toObject(serialized);
+
+		assertThat(originalSession.getCreationTime()).isEqualTo(cached.getCreationTime());
+		assertThat(originalSession.getMaxInactiveInterval()).isEqualTo(cached.getMaxInactiveInterval());
+		assertThat(originalSession.getId()).isEqualTo(cached.getId());
+		assertThat(originalSession.getOriginalId()).isEqualTo(cached.getOriginalId());
+		assertThat(originalSession.getAttributeNames().size()).isEqualTo(cached.getAttributeNames().size());
+		assertThat(originalSession.<String>getAttribute("attr1"))
+				.isEqualTo(cached.getAttribute("attr1"));
+		assertThat(originalSession.<String>getAttribute("attr2"))
+				.isEqualTo(cached.getAttribute("attr2"));
+		assertThat(originalSession.<SerializableTestAttribute>getAttribute("attr3"))
+				.isEqualTo(cached.getAttribute("attr3"));
+	}
+
+
+	static class SerializableTestAttribute implements Serializable {
+
+		private int id;
+
+		public SerializableTestAttribute(int id) {
+			this.id = id;
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if (this == o) return true;
+			if (!(o instanceof SerializableTestAttribute)) return false;
+			SerializableTestAttribute that = (SerializableTestAttribute) o;
+			return id == that.id;
+		}
+
+		@Override
+		public int hashCode() {
+			return id;
+		}
+	}
+
+}

From c8d73a3b0eb53ce04db66518327545a734a09d58 Mon Sep 17 00:00:00 2001
From: Enes Ozcan <enes.ozcan@hazelcast.com>
Date: Fri, 7 Aug 2020 16:02:50 +0300
Subject: [PATCH 6/7] Fix checkstyle.

---
 .../hazelcast/HazelcastITestUtils.java        |  1 +
 .../hazelcast/HazelcastSessionSerializer.java | 61 ++++++++++++-------
 ...a => HazelcastSessionSerializerTests.java} | 56 +++++++++++------
 3 files changed, 78 insertions(+), 40 deletions(-)
 rename spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/{HazelcastSessionSerializerTest.java => HazelcastSessionSerializerTests.java} (60%)

diff --git a/spring-session-hazelcast/src/integration-test/java/org/springframework/session/hazelcast/HazelcastITestUtils.java b/spring-session-hazelcast/src/integration-test/java/org/springframework/session/hazelcast/HazelcastITestUtils.java
index 608de19c2..76158a0d5 100644
--- a/spring-session-hazelcast/src/integration-test/java/org/springframework/session/hazelcast/HazelcastITestUtils.java
+++ b/spring-session-hazelcast/src/integration-test/java/org/springframework/session/hazelcast/HazelcastITestUtils.java
@@ -23,6 +23,7 @@
 import com.hazelcast.config.SerializerConfig;
 import com.hazelcast.core.Hazelcast;
 import com.hazelcast.core.HazelcastInstance;
+
 import org.springframework.session.MapSession;
 
 /**
diff --git a/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java b/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
index 65d9ec402..27c94cef7 100644
--- a/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
+++ b/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
@@ -1,32 +1,49 @@
-package org.springframework.session.hazelcast;
+/*
+ * Copyright 2014-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 
-import com.hazelcast.nio.ObjectDataInput;
-import com.hazelcast.nio.ObjectDataOutput;
-import com.hazelcast.nio.serialization.StreamSerializer;
-import org.springframework.session.MapSession;
+package org.springframework.session.hazelcast;
 
 import java.io.EOFException;
 import java.io.IOException;
 import java.time.Duration;
 import java.time.Instant;
 
+import com.hazelcast.nio.ObjectDataInput;
+import com.hazelcast.nio.ObjectDataOutput;
+import com.hazelcast.nio.serialization.StreamSerializer;
+
+import org.springframework.session.MapSession;
+
 /**
- * A {@link com.hazelcast.nio.serialization.Serializer} implementation that
- * handles the (de)serialization of {@link MapSession} stored on {@link com.hazelcast.core.IMap}.
+ * A {@link com.hazelcast.nio.serialization.Serializer} implementation that handles the
+ * (de)serialization of {@link MapSession} stored on {@link com.hazelcast.core.IMap}.
  *
  * <p>
- * The use of this serializer is optional and provides faster serialization of
- * sessions. If not configured to be used, Hazelcast will serialize sessions
- * via {@link java.io.Serializable} by default.
+ * The use of this serializer is optional and provides faster serialization of sessions.
+ * If not configured to be used, Hazelcast will serialize sessions via
+ * {@link java.io.Serializable} by default.
  *
  * <p>
- * If multiple instances of a Spring application is run, then all of them need to use
- * the same serialization method. If this serializer is registered on one instance
- * and not another one, then it will end up with HazelcastSerializationException.
- * The same applies when clients are configured to use this serializer but not the
- * members, and vice versa. Also note that, if a new instance is created with this
- * serialization but the existing Hazelcast cluster contains the values not serialized
- * by this but instead the default one, this will result in incompatibility again.
+ * If multiple instances of a Spring application is run, then all of them need to use the
+ * same serialization method. If this serializer is registered on one instance and not
+ * another one, then it will end up with HazelcastSerializationException. The same applies
+ * when clients are configured to use this serializer but not the members, and vice versa.
+ * Also note that, if a new instance is created with this serialization but the existing
+ * Hazelcast cluster contains the values not serialized by this but instead the default
+ * one, this will result in incompatibility again.
  *
  * <p>
  * An example of how to register the serializer on embedded instance can be seen below:
@@ -44,9 +61,10 @@
  * </pre>
  *
  * Below is the example of how to register the serializer on client instance. Note that,
- * to use the serializer in client/server mode, the serializer - and hence {@link MapSession},
- * must exist on the server's classpath and must be registered via {@link com.hazelcast.config.SerializerConfig}
- * with the configuration above for each server.
+ * to use the serializer in client/server mode, the serializer - and hence
+ * {@link MapSession}, must exist on the server's classpath and must be registered via
+ * {@link com.hazelcast.config.SerializerConfig} with the configuration above for each
+ * server.
  *
  * <pre class="code">
  * ClientConfig clientConfig = new ClientConfig();
@@ -110,7 +128,8 @@ public MapSession read(ObjectDataInput in) throws IOException {
 				Object attrValue = in.readObject();
 				cached.setAttribute(attrName, attrValue);
 			}
-		} catch (EOFException ignored) {
+		}
+		catch (EOFException ignored) {
 		}
 		return cached;
 	}
diff --git a/spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/HazelcastSessionSerializerTest.java b/spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/HazelcastSessionSerializerTests.java
similarity index 60%
rename from spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/HazelcastSessionSerializerTest.java
rename to spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/HazelcastSessionSerializerTests.java
index 17e749f57..b79a3bf1e 100644
--- a/spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/HazelcastSessionSerializerTest.java
+++ b/spring-session-hazelcast/src/test/java/org/springframework/session/hazelcast/HazelcastSessionSerializerTests.java
@@ -1,5 +1,25 @@
+/*
+ * Copyright 2014-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package org.springframework.session.hazelcast;
 
+import java.io.Serializable;
+import java.time.Duration;
+import java.time.Instant;
+
 import com.hazelcast.config.SerializationConfig;
 import com.hazelcast.config.SerializerConfig;
 import com.hazelcast.internal.serialization.impl.DefaultSerializationServiceBuilder;
@@ -7,11 +27,8 @@
 import com.hazelcast.spi.serialization.SerializationService;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
-import org.springframework.session.MapSession;
 
-import java.io.Serializable;
-import java.time.Duration;
-import java.time.Instant;
+import org.springframework.session.MapSession;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -22,11 +39,10 @@ class HazelcastSessionSerializerTests {
 	@BeforeEach
 	void setUp() {
 		SerializationConfig serializationConfig = new SerializationConfig();
-		SerializerConfig serializerConfig = new SerializerConfig()
-				.setImplementation(new HazelcastSessionSerializer())
+		SerializerConfig serializerConfig = new SerializerConfig().setImplementation(new HazelcastSessionSerializer())
 				.setTypeClass(MapSession.class);
 		serializationConfig.addSerializerConfig(serializerConfig);
-		serializationService = new DefaultSerializationServiceBuilder().setConfig(serializationConfig).build();
+		this.serializationService = new DefaultSerializationServiceBuilder().setConfig(serializationConfig).build();
 	}
 
 	@Test
@@ -39,43 +55,45 @@ void serializeSessionWithStreamSerializer() {
 		originalSession.setLastAccessedTime(Instant.now());
 		originalSession.setId("custom-id");
 
-		Data serialized = serializationService.toData(originalSession);
-		MapSession cached = serializationService.toObject(serialized);
+		Data serialized = this.serializationService.toData(originalSession);
+		MapSession cached = this.serializationService.toObject(serialized);
 
 		assertThat(originalSession.getCreationTime()).isEqualTo(cached.getCreationTime());
 		assertThat(originalSession.getMaxInactiveInterval()).isEqualTo(cached.getMaxInactiveInterval());
 		assertThat(originalSession.getId()).isEqualTo(cached.getId());
 		assertThat(originalSession.getOriginalId()).isEqualTo(cached.getOriginalId());
 		assertThat(originalSession.getAttributeNames().size()).isEqualTo(cached.getAttributeNames().size());
-		assertThat(originalSession.<String>getAttribute("attr1"))
-				.isEqualTo(cached.getAttribute("attr1"));
-		assertThat(originalSession.<String>getAttribute("attr2"))
-				.isEqualTo(cached.getAttribute("attr2"));
+		assertThat(originalSession.<String>getAttribute("attr1")).isEqualTo(cached.getAttribute("attr1"));
+		assertThat(originalSession.<String>getAttribute("attr2")).isEqualTo(cached.getAttribute("attr2"));
 		assertThat(originalSession.<SerializableTestAttribute>getAttribute("attr3"))
 				.isEqualTo(cached.getAttribute("attr3"));
 	}
 
-
 	static class SerializableTestAttribute implements Serializable {
 
 		private int id;
 
-		public SerializableTestAttribute(int id) {
+		SerializableTestAttribute(int id) {
 			this.id = id;
 		}
 
 		@Override
 		public boolean equals(Object o) {
-			if (this == o) return true;
-			if (!(o instanceof SerializableTestAttribute)) return false;
+			if (this == o) {
+				return true;
+			}
+			if (!(o instanceof SerializableTestAttribute)) {
+				return false;
+			}
 			SerializableTestAttribute that = (SerializableTestAttribute) o;
-			return id == that.id;
+			return this.id == that.id;
 		}
 
 		@Override
 		public int hashCode() {
-			return id;
+			return this.id;
 		}
+
 	}
 
 }

From f1a832e0266172705ca1f6d8b0e3ad84d7a3ad19 Mon Sep 17 00:00:00 2001
From: Enes Ozcan <enes.ozcan@hazelcast.com>
Date: Tue, 8 Sep 2020 13:37:48 +0300
Subject: [PATCH 7/7] Add since tag.

---
 .../session/hazelcast/HazelcastSessionSerializer.java            | 1 +
 1 file changed, 1 insertion(+)

diff --git a/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java b/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
index 27c94cef7..d88df92b7 100644
--- a/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
+++ b/spring-session-hazelcast/src/main/java/org/springframework/session/hazelcast/HazelcastSessionSerializer.java
@@ -79,6 +79,7 @@
  * </pre>
  *
  * @author Enes Ozcan
+ * @since 2.4.0
  */
 public class HazelcastSessionSerializer implements StreamSerializer<MapSession> {