This is code with the error. IDE: Eclipse
EDIT: I used addArguments but the error still there,
Based on the documentation, the method name should be addArguments not AddArgument. By the way, Java uses camelCase for methods by convention. The code you currently have is a correct C# code, so it seems that you've copied a C# snippet from somewhere.
If the error still exists, try clean & rebuilding the project or restarting the IDE and/or your PC. It might be that "Eclipse" just have some weird problem.
You wrote the name of the function incorrectly, it is options.addArguments("--incognito");