perf(core): [SDK Overhead Reduction 12] Avoid cloning Date getters

sentry/src/main/java/io/sentry/Breadcrumb.java

@@ -553,7 +553,7 @@ public Breadcrumb(@Nullable String message) {
   @SuppressWarnings("JavaUtilDate")
   public @NotNull Date getTimestamp() {
     if (timestamp != null) {
-      return (Date) timestamp.clone();
+      return timestamp;
     } else if (timestampMs != null) {
       // we memoize it here into timestamp to avoid instantiating Calendar again and again
       timestamp = DateUtils.getDateTime(timestampMs);

sentry/src/main/java/io/sentry/SentryEvent.java

@@ -114,7 +114,7 @@ public SentryEvent(final @NotNull Date timestamp) {
 
   @SuppressWarnings({"JdkObsolete", "JavaUtilDate"})
   public Date getTimestamp() {
-    return (Date) timestamp.clone();
+    return timestamp;
   }
 
   public void setTimestamp(final @NotNull Date timestamp) {

sentry/src/main/java/io/sentry/Session.java

@@ -131,10 +131,7 @@ public boolean isTerminated() {
 
   @SuppressWarnings({"JdkObsolete", "JavaUtilDate"})
   public @Nullable Date getStarted() {
-    if (started == null) {
-      return null;
-    }
-    return (Date) started.clone();
+    return started;
   }
 
   public @Nullable String getDistinctId() {
@@ -193,8 +190,7 @@ public int errorCount() {
 
   @SuppressWarnings({"JdkObsolete", "JavaUtilDate"})
   public @Nullable Date getTimestamp() {
-    final Date timestampRef = timestamp;
-    return timestampRef != null ? (Date) timestampRef.clone() : null;
+    return timestamp;
   }
 
   /** Ends a session and update its values */

sentry/src/main/java/io/sentry/protocol/App.java

@@ -98,8 +98,7 @@ public void setAppIdentifier(final @Nullable String appIdentifier) {
 
   @SuppressWarnings({"JdkObsolete", "JavaUtilDate"})
   public @Nullable Date getAppStartTime() {
-    final Date appStartTimeRef = appStartTime;
-    return appStartTimeRef != null ? (Date) appStartTimeRef.clone() : null;
+    return appStartTime;
   }
 
   public void setAppStartTime(final @Nullable Date appStartTime) {

sentry/src/main/java/io/sentry/protocol/Device.java

@@ -366,8 +366,7 @@ public void setScreenDpi(final @Nullable Integer screenDpi) {
 
   @SuppressWarnings({"JdkObsolete", "JavaUtilDate"})
   public @Nullable Date getBootTime() {
-    final Date bootTimeRef = bootTime;
-    return bootTimeRef != null ? (Date) bootTimeRef.clone() : null;
+    return bootTime;
   }
 
   public void setBootTime(final @Nullable Date bootTime) {

sentry/src/test/java/io/sentry/protocol/AppTest.kt

@@ -5,10 +5,11 @@ import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertNotNull
 import kotlin.test.assertNotSame
+import kotlin.test.assertSame
 
 class AppTest {
   @Test
-  fun `copying app wont have the same references`() {
+  fun `copying app keeps date reference and copies collections`() {
     val app = App()
     app.appBuild = "app build"
     app.appIdentifier = "app identifier"
@@ -28,7 +29,7 @@ class AppTest {
 
     assertNotNull(clone)
     assertNotSame(app, clone)
-    assertNotSame(app.appStartTime, clone.appStartTime)
+    assertSame(app.appStartTime, clone.appStartTime)
     assertNotSame(app.permissions, clone.permissions)
     assertNotSame(app.viewNames, clone.viewNames)
 

sentry/src/test/java/io/sentry/protocol/DeviceTest.kt

@@ -6,11 +6,12 @@ import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertNotNull
 import kotlin.test.assertNotSame
+import kotlin.test.assertSame
 
 class DeviceTest {
 
   @Test
-  fun `copying device wont have the same references`() {
+  fun `copying device keeps date reference and copies other mutable references`() {
     val device = Device()
     device.archs = arrayOf("archs1", "archs2")
     device.bootTime = Date()
@@ -23,7 +24,7 @@ class DeviceTest {
     assertNotNull(clone)
     assertNotSame(device, clone)
     assertNotSame(device.archs, clone.archs)
-    assertNotSame(device.bootTime, clone.bootTime)
+    assertSame(device.bootTime, clone.bootTime)
     assertNotSame(device.timezone, clone.timezone)
     assertNotSame(device.unknown, clone.unknown)
   }