[docs update] java 新特性部分内容完善

Author: Snailclimb

docs/java/new-features/java12-13.md

@@ -269,8 +269,8 @@ public String translateEscapes() {
 ## 参考
 
 - JDK Project Overview ： <https://openjdk.java.net/projects/jdk/ >
-- Oracle Java12 ReleaseNote <https://www.oracle.com/technetwork/java/javase/12all-relnotes-5211423.html#NewFeature>
+- Oracle Java12 ReleaseNote ：https://www.oracle.com/java/technologies/javase/12all-relnotes.htm
+- What is new in Java 12：https://mkyong.com/java/what-is-new-in-java-12/
 - Oracle Java13 ReleaseNote <https://www.oracle.com/technetwork/java/javase/13all-relnotes-5461743.html#NewFeature>
-- New Features in Java 12 <https://www.baeldung.com/java-12-new-features>
 - New Java13 Features <https://www.baeldung.com/java-13-new-features>
 - Java13 新特性概述 <https://www.ibm.com/developerworks/cn/java/the-new-features-of-Java-13/index.html>

docs/java/new-features/java9.md

@@ -238,8 +238,7 @@ System.out.println(currentProcess.info());
 
 ## 参考
 
+- Release Notes for JDK 9 and JDK 9 Update Releases : https://www.oracle.com/java/technologies/javase/9-all-relnotes.html
 - 《深入剖析 Java 新特性》-极客时间 - JShell：怎么快速验证简单的小问题？
-
 - New Features in Java 9:https://www.baeldung.com/new-java-9
-
 - Java – Try with Resources：https://www.baeldung.com/java-try-with-resources