RocMarshal commented on a change in pull request #16753:
URL: https://github.com/apache/flink/pull/16753#discussion_r686451547
##########
File path: docs/content.zh/docs/dev/datastream/java_lambdas.md
##########
@@ -25,37 +24,34 @@ specific language governing permissions and limitations
under the License.
-->
-# Java Lambda Expressions
+# Java Lambda 表达式
-Java 8 introduced several new language features designed for faster and
clearer coding. With the most important feature,
-the so-called "Lambda Expressions", it opened the door to functional
programming. Lambda expressions allow for implementing and
-passing functions in a straightforward way without having to declare
additional (anonymous) classes.
+Java 8 引入了几种新的语言特性，旨在实现更快、更清晰的编码。作为最重要的特性，即所谓的“Lambda 表达式”，它开启了函数式编程的大门。Lambda
表达式允许以简捷的方式实现和传递函数，而无需声明额外的（匿名）类。
{{< hint info >}}
-Flink supports the usage of lambda expressions for all operators of the Java
API, however, whenever a lambda expression uses Java generics you need to
declare type information *explicitly*.
+Flink 支持对 Java API 的所有算子使用 Lambda 表达式，但是，当 Lambda 表达式使用 Java 泛型时，你需要 *显式*
地声明类型信息。
{{< /hint >}}
-This document shows how to use lambda expressions and describes current
-limitations. For a general introduction to the Flink API, please refer to the
-[DataSteam API overview]({{< ref "docs/dev/datastream/overview" >}})
+本文档介绍如何使用 Lambda 表达式并描述了其（Lambda 表达式）当前的限制。有关 Flink API 的通用介绍，请参阅 [DataStream
API 编程指南]({{< ref "docs/dev/datastream/overview" >}})。
-### Examples and Limitations
+## 示例和限制
-The following example illustrates how to implement a simple, inline `map()`
function that squares its input using a lambda expression.
-The types of input `i` and output parameters of the `map()` function need not
to be declared as they are inferred by the Java compiler.
+下面的这个示例演示了如何实现一个简单的内联 `map()` 函数，它使用 Lambda 表达式计算输入值的平方。
+
+不需要声明 `map()` 函数的输入 `i` 和输出参数的数据类型，因为 Java 编译器会对它们做出推断。
```java
env.fromElements(1, 2, 3)
-// returns the squared i
+// 返回 i 的平方
.map(i -> i*i)
.print();
```
-Flink can automatically extract the result type information from the
implementation of the method signature `OUT map(IN value)` because `OUT` is not
generic but `Integer`.
+由于 `OUT` 是 `Integer` 而不是泛型，所以 Flink 可以从方法签名 `OUT map(IN value)`
的实现中自动提取出结果的类型信息。
-Unfortunately, functions such as `flatMap()` with a signature `void flatMap(IN
value, Collector<OUT> out)` are compiled into `void flatMap(IN value, Collector
out)` by the Java compiler. This makes it impossible for Flink to infer the
type information for the output type automatically.
+不幸的是，像 `flatMap()` 这样的函数，它的签名 `void flatMap(IN value, Collector<OUT> out)` 被
Java 编译器编译为 `void flatMap(IN value, Collector out)`。这样 Flink 就无法自动推断输出的类型信息了。
-Flink will most likely throw an exception similar to the following:
+Flink 很可能抛出类似如下的异常：
Review comment:
```suggestion
Flink 很可能抛出如下异常：
```
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
