Java: How do I create this JSON Array Structure using GSON

I want to create a JSON array structure like this or append an object to the structure

{ "user" : [
     {"name" : "user1", "email": "user1@gmail"},
     {"name": "user2", "email": "user2@gmail"}
   ]
}

I'm using GSON to write this into a file

    public void appendToObject(File jsonFile, String key, String value)  {
Objects.requireNonNull(jsonFile);
Objects.requireNonNull(key);
Objects.requireNonNull(value);
if (jsonFile.isDirectory()) {
throw new IllegalArgumentException("File can not be a directory!");
}
try {
JsonObject node = readOrCreateNew(jsonFile);
JsonArray userArray = new JsonArray();
userArray.add(user(key,value));
node.add("user", userArray);
FileWriter writer = new FileWriter(jsonFile)
gson.toJson(node, writer);
}catch (Exception e)
{
Log.d("display1", "appendToObject: error"+e.getLocalizedMessage());
e.printStackTrace();
}
}
private JsonObject user(String user, String password){
JsonObject jsonObject = new JsonObject();
jsonObject.addProperty("name", user);
jsonObject.addProperty("password", password);
return jsonObject;
}
private JsonObject readOrCreateNew(File jsonFile) throws IOException {
if (jsonFile.exists() && jsonFile.length() > 0) {
try (BufferedReader reader = new BufferedReader(new FileReader(jsonFile))) {
return gson.fromJson(reader, JsonObject.class);
}
}
return new JsonObject();
}

Here's the code with suggestions integrated and with reading and writing JSON file functions

but im getting "user1":"{\"values\":[null,\"user13\",\"useremail13\"]}"}

how to structure it so that I get the desired output

I omitted some your code in appendToObject. But the meaning should be clear.

  public void appendToObject(File jsonFile, String key, String value)  {

    ...

    JsonObject node = readOrCreateNew(jsonFile);
  
    JsonObject newUser = user(key, value);
    JsonElement user = node.get("user");
    
    if (user != null && user.isJsonArray()){
      ((JsonArray) user).add(newUser);
    } else {
      JsonObject root = new JsonObject();
      node.add("user", createArray(newUser));
    }
     
    ...
  }

  private JsonObject createUserArray(JsonObject ... objects){
    JsonArray userArray = new JsonArray();
    for (JsonObject user : objects) {
      userArray.add(user);
    }
    return userArray;
  }

  private JsonObject user(String email, String name){
    JsonObject jsonObject = new JsonObject();
    jsonObject.addProperty("name", name);
    jsonObject.addProperty("email", email);
    return jsonObject;
  }