Use Instant for Session creation and last accessed times

Closes gh-10976

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/session/SessionsEndpoint.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.boot.actuate.session;
 
+import java.time.Instant;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -101,9 +102,9 @@ public class SessionsEndpoint {
 
 		private final Set<String> attributeNames;
 
-		private final long creationTime;
+		private final Instant creationTime;
 
-		private final long lastAccessedTime;
+		private final Instant lastAccessedTime;
 
 		private final long maxInactiveInterval;
 
@@ -112,8 +113,8 @@ public class SessionsEndpoint {
 		public SessionDescriptor(Session session) {
 			this.id = session.getId();
 			this.attributeNames = session.getAttributeNames();
-			this.creationTime = session.getCreationTime().toEpochMilli();
-			this.lastAccessedTime = session.getLastAccessedTime().toEpochMilli();
+			this.creationTime = session.getCreationTime();
+			this.lastAccessedTime = session.getLastAccessedTime();
 			this.maxInactiveInterval = session.getMaxInactiveInterval().getSeconds();
 			this.expired = session.isExpired();
 		}
@@ -126,11 +127,11 @@ public class SessionsEndpoint {
 			return this.attributeNames;
 		}
 
-		public long getCreationTime() {
+		public Instant getCreationTime() {
 			return this.creationTime;
 		}
 
-		public long getLastAccessedTime() {
+		public Instant getLastAccessedTime() {
 			return this.lastAccessedTime;
 		}
 

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/session/SessionsEndpointTests.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -57,10 +57,9 @@ public class SessionsEndpointTests {
 		assertThat(result.get(0).getId()).isEqualTo(session.getId());
 		assertThat(result.get(0).getAttributeNames())
 				.isEqualTo(session.getAttributeNames());
-		assertThat(result.get(0).getCreationTime())
-				.isEqualTo(session.getCreationTime().toEpochMilli());
+		assertThat(result.get(0).getCreationTime()).isEqualTo(session.getCreationTime());
 		assertThat(result.get(0).getLastAccessedTime())
-				.isEqualTo(session.getLastAccessedTime().toEpochMilli());
+				.isEqualTo(session.getLastAccessedTime());
 		assertThat(result.get(0).getMaxInactiveInterval())
 				.isEqualTo(session.getMaxInactiveInterval().getSeconds());
 		assertThat(result.get(0).isExpired()).isEqualTo(session.isExpired());
@@ -72,10 +71,8 @@ public class SessionsEndpointTests {
 		SessionDescriptor result = this.endpoint.getSession(session.getId());
 		assertThat(result.getId()).isEqualTo(session.getId());
 		assertThat(result.getAttributeNames()).isEqualTo(session.getAttributeNames());
-		assertThat(result.getCreationTime())
-				.isEqualTo(session.getCreationTime().toEpochMilli());
-		assertThat(result.getLastAccessedTime())
-				.isEqualTo(session.getLastAccessedTime().toEpochMilli());
+		assertThat(result.getCreationTime()).isEqualTo(session.getCreationTime());
+		assertThat(result.getLastAccessedTime()).isEqualTo(session.getLastAccessedTime());
 		assertThat(result.getMaxInactiveInterval())
 				.isEqualTo(session.getMaxInactiveInterval().getSeconds());
 		assertThat(result.isExpired()).isEqualTo(session.isExpired());