doc: Update java.md (#311)

添加List和Set集合中打印时使用lamba输出的方式。
2023-02-23 23:34:24 +08:00 · 2023-02-23 23:34:24 +08:00 · 2348522810
commit 2348522810
parent 5ca71fdb60
1 changed files with 3 additions and 0 deletions
--- a/docs/java.md
+++ b/docs/java.md
@ -595,6 +595,8 @@ nums.remove(0); // 非常慢
 for (Integer value : nums) {
    System.out.println(value);
 }
+// lambda 打印元素
+nums.forEach(e -> System.out.println(e.toString()));
 ```

 ### HashMap
@ -653,6 +655,7 @@ set.remove("cat");
 for (String element : set) {
    System.out.println(element);
 }
+set.forEach(e -> System.out.println(e.toString()));
 ```

 ### ArrayDeque