AWS DUPLICATE_CLIENT_ID指的是在AWS OAuth2.0身份验证流程中，客户端ID重复的错误。解决方法是要确保在使用AWS OAuth2.0进行身份验证时，不要在任何地方使用同样的客户端ID。如果已经使用了相同的客户端ID，可以通过更改其名称来解决此问题。例如，以下代码演示如何使用AWS Java SDK更改客户端ID名称：

import com.amazonaws.services.cognitoidp.AWSCognitoIdentityProvider;
import com.amazonaws.services.cognitoidp.AWSCognitoIdentityProviderClientBuilder;
import com.amazonaws.services.cognitoidp.model.UpdateUserPoolClientRequest;
import com.amazonaws.services.cognitoidp.model.UpdateUserPoolClientResult;


public class Example {

    public static void main(String[] args) {
        final String CLIENT_ID = "myClientId";
        final String NEW_CLIENT_ID = "myNewClientId";
        final String USER_POOL_ID = "myUserPoolId";

        final AWSCognitoIdentityProvider cognitoClient = AWSCognitoIdentityProviderClientBuilder.defaultClient();

        final UpdateUserPoolClientRequest updateRequest = new UpdateUserPoolClientRequest()
            .withClientId(CLIENT_ID)
            .withUserPoolId(USER_POOL_ID)
            .withClientName(NEW_CLIENT_ID);

        final UpdateUserPoolClientResult updateResult = cognitoClient.updateUserPoolClient(updateRequest);

        System.out.println("Updated client name: " + updateResult.getUserPoolClient().getClientName());
    }
}