我的 GWT 项目需要为 java.io 和 java.nio 继承什么模块?

What module do I need to inherit for java.io and java.nio for my GWT project?

我正在尝试遵循这个例子:

Charset utf8 = StandardCharsets.UTF_8;
List<String> lines = Arrays.asList("1st line", "2nd line");
try {
    Files.write(Paths.get("file5-test.txt"), lines, utf8);
} catch (IOException e) {
    e.printStackTrace();
}

我已经导入了所需的模块:

import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;    

但是我在编译时遇到了以下错误:

[ERROR] Errors in 'file:/C:/Users/Glyndwr/workspace/AwardTracker_N/src/org/AwardTracker/client/PackSummaryView.java'
[ERROR] Line 309: No source code is available for type java.nio.charset.Charset; did you forget to inherit a required module?
[ERROR] Line 309: No source code is available for type java.nio.charset.StandardCharsets; did you forget to inherit a required module?
[ERROR] Line 313: No source code is available for type java.nio.file.Files; did you forget to inherit a required module?
[ERROR] Line 313: No source code is available for type java.nio.file.Paths; did you forget to inherit a required module?  

我想我需要添加到我的 AwardTracker.gwt.xml:

<inherits name="module name/>"

但是,我找不到要继承的正确模块名称。
另外,有没有我需要导入的jar?

非常感谢您的帮助。

问候,格林

这看起来像是服务器端代码,不应该是 GWT 客户端的一部分。