diff --git a/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/ChatSession.java b/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/ChatSession.java
index 41df20360c2b..3f4ad24702b6 100644
--- a/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/ChatSession.java
+++ b/java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/ChatSession.java
@@ -92,7 +92,7 @@ public ChatSession withSafetySettings(List<SafetySetting> safetySettings) {
     ChatSession rootChat = rootChatSession.orElse(this);
     ChatSession newChatSession =
         new ChatSession(model.withSafetySettings(safetySettings), Optional.of(rootChat));
-    newChatSession.setHistory(history);
+    newChatSession.history = history;
     return newChatSession;
   }
 
@@ -106,7 +106,7 @@ public ChatSession withSafetySettings(List<SafetySetting> safetySettings) {
   public ChatSession withTools(List<Tool> tools) {
     ChatSession rootChat = rootChatSession.orElse(this);
     ChatSession newChatSession = new ChatSession(model.withTools(tools), Optional.of(rootChat));
-    newChatSession.setHistory(history);
+    newChatSession.history = history;
     return newChatSession;
   }
 
@@ -253,7 +253,7 @@ private Optional<ResponseStream<GenerateContentResponse>> getCurrentResponseStre
 
   /** Set the history to a list of Content */
   public void setHistory(List<Content> history) {
-    this.history = history;
+    this.history = new ArrayList<>(history);
   }
 
   /** Sets the current response of the root chat session (if exists) or the current chat session. */