如何防止foreach循环不删除重复项

import com.tencentcloudapi.tdsql.v20180228.TdsqlClient;
import com.tencentcloudapi.tdsql.v20180228.models.DescribeDatabasesRequest;
import com.tencentcloudapi.tdsql.v20180228.models.DescribeDatabasesResponse;
import com.tencentcloudapi.tdsql.v20180228.models.Database;

import java.util.HashSet;
import java.util.Set;

public class Main {
    public static void main(String[] args) {
        // 创建TDSQL客户端
        TdsqlClient client = new TdsqlClient();

        // 创建请求对象
        DescribeDatabasesRequest request = new DescribeDatabasesRequest();
        request.setInstanceId("实例ID");

        // 发送请求并获取响应
        DescribeDatabasesResponse response = client.DescribeDatabases(request);

        // 创建Set集合用于存储数据库名字
        Set<String> databaseNames = new HashSet<>();

        // 遍历响应中的数据库列表
        for (Database database : response.getDatabases()) {
            // 将数据库名字添加到Set集合中
            databaseNames.add(database.getDatabaseName());
        }

        // 输出去重后的数据库名字
        for (String name : databaseNames) {
            System.out.println(name);
        }
    }
}

import com.tencentcloudapi.tdsql.v20180228.TdsqlClient;
import com.tencentcloudapi.tdsql.v20180228.models.DescribeDatabasesRequest;
import com.tencentcloudapi.tdsql.v20180228.models.DescribeDatabasesResponse;
import com.tencentcloudapi.tdsql.v20180228.models.Database;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class Main {
    public static void main(String[] args) {
        // 创建TDSQL客户端
        TdsqlClient client = new TdsqlClient();

        // 创建请求对象
        DescribeDatabasesRequest request = new DescribeDatabasesRequest();
        request.setInstanceId("实例ID");

        // 发送请求并获取响应
        DescribeDatabasesResponse response = client.DescribeDatabases(request);

        // 创建HashMap用于标记已经出现的数据库名字
        Map<String, Integer> databaseMap = new HashMap<>();

        // 遍历响应中的数据库列表
        Iterator<Database> iterator = response.getDatabases().iterator();
        while (iterator.hasNext()) {
            Database database = iterator.next();
            String databaseName = database.getDatabaseName();

            // 如果数据库名字已经出现过，则从集合中删除该元素
            if (databaseMap.containsKey(databaseName)) {
                iterator.remove();
            } else {
                // 否则将数据库名字添加到HashMap中
                databaseMap.put(databaseName, 1);
            }
        }

        // 输出去重后的数据库列表
        for (Database database : response.getDatabases()) {
            System.out.println(database.getDatabaseName());
        }
    }
}