标签: java-11

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> Task :react-native-gradle-plugin:compileKotlin FAILED
'compileJava' task (current target is 1.8) and 'compileKotlin' task (current target is 11) jvm target compatibility should be set to the same Java version.
1 actionable task: 1 executed

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task …

我希望JMC能够与OpenJDK,JDK11二进制文件一起使用,因为它已经由Oracle 11从Java 11开源,但无法在Oracle文件夹中找到Oracle和AdoptOpenJDK Java-11二进制文件.我也试过这个https://jdk.java.net/jmc/,因为有些文章说它是单独发布的.有谁知道如何获得OpenJDK-11的JMC.

在使用Java 11在Intellij IDEA中提取变量(ctrl + alt + v)时,我希望默认情况下将其提取为a var而不是详细类型.

var home = "127.0.0.1";

代替

String home = "127.0.0.1";

有没有办法配置Intellij IDEA来做到这一点？

我使用的是新 java.net.http.HttpClient与sendAsync方法.该HttpClient是Singelton内创建一次像这样: HttpClient.newBuilder().build()所以真的没什么特别的.

这些请求可以是POST,GET但我不知道是哪个引起了麻烦.

每天只有几个请求,但有时一个线程使用100%的cpu核心.并不是迫在眉睫,而是在请求完成一段时间后.

所以我做了一个线程转储,甚至有两个无限循环发生,以下2个线程突出:

"HttpClient-4-Worker-5" #144 daemon prio=5 os_prio=0 cpu=511298.10ms elapsed=520.71s tid=0x00007f684403e800 nid=0x2d6b runnable  [0x00007f68ac162000]
   java.lang.Thread.State: RUNNABLE
        at jdk.internal.net.http.common.SSLFlowDelegate$Writer.processData(java.net.http@11.0.2/SSLFlowDelegate.java:771)
        at jdk.internal.net.http.common.SSLFlowDelegate$Writer$WriterDownstreamPusher.run(java.net.http@11.0.2/SSLFlowDelegate.java:645)
        at jdk.internal.net.http.common.SequentialScheduler$CompleteRestartableTask.run(java.net.http@11.0.2/SequentialScheduler.java:147)
        at jdk.internal.net.http.common.SequentialScheduler$SchedulableTask.run(java.net.http@11.0.2/SequentialScheduler.java:198)
        at jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(java.net.http@11.0.2/SequentialScheduler.java:271)
        at jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(java.net.http@11.0.2/SequentialScheduler.java:224)
        at jdk.internal.net.http.common.SSLFlowDelegate$Writer.triggerWrite(java.net.http@11.0.2/SSLFlowDelegate.java:722)
        at jdk.internal.net.http.common.SSLFlowDelegate.doHandshake(java.net.http@11.0.2/SSLFlowDelegate.java:1024)
        at jdk.internal.net.http.common.SSLFlowDelegate.doClosure(java.net.http@11.0.2/SSLFlowDelegate.java:1094)
        at jdk.internal.net.http.common.SSLFlowDelegate$Reader.unwrapBuffer(java.net.http@11.0.2/SSLFlowDelegate.java:500)
        at jdk.internal.net.http.common.SSLFlowDelegate$Reader.processData(java.net.http@11.0.2/SSLFlowDelegate.java:389)
        - locked <0x00000000fba68950> (a java.lang.Object)
        at jdk.internal.net.http.common.SSLFlowDelegate$Reader$ReaderDownstreamPusher.run(java.net.http@11.0.2/SSLFlowDelegate.java:263)
        at jdk.internal.net.http.common.SequentialScheduler$SynchronizedRestartableTask.run(java.net.http@11.0.2/SequentialScheduler.java:175)
        - locked <0x00000000fbbca3e8> (a java.lang.Object)
        at jdk.internal.net.http.common.SequentialScheduler$CompleteRestartableTask.run(java.net.http@11.0.2/SequentialScheduler.java:147)
        at jdk.internal.net.http.common.SequentialScheduler$SchedulableTask.run(java.net.http@11.0.2/SequentialScheduler.java:198)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@11.0.2/ThreadPoolExecutor.java:1128)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@11.0.2/ThreadPoolExecutor.java:628)
        at java.lang.Thread.run(java.base@11.0.2/Thread.java:834)

   Locked ownable …

考虑以下代码：

public static void main(String[] args) {
    Stream.iterate(1, i -> i + 1)
            .flatMap(i -> Stream.of(i, i, i))
            .peek(System.out::println)
            .limit(4)
            .forEach(i -> {});
}

Java 8的输出：

1
1
1
2
2
2

在Java 11中：

1
1
1
2

这是Java 8中的错误或预期的行为，在11中进行了更改吗？

上面的代码只是演示不同行为的示例，但是更重要的含义是，以下代码在Java 11中显示1,2,3，但在Java 8中进入了无限循环：

    Stream.iterate(0, i -> i + 10)
            .flatMap(i -> Stream.iterate(i + 1, j -> j + 1))
            .limit(3)
            .forEach(System.out::println);

我正在从 Java 8 迁移到 Java 11 并遇到了这个问题。我应该使用：

• maven-compiler-plugin 2.5.1 与目标 1.8（在 java8 中编译 WAR）
• tomcat9
• 打开 JDK 11

但是在启动时不断出现错误：

合并bean定义后处理失败；嵌套异常是 java.lang.NoSuchMethodError: javax.annotation.Resource.lookup()Ljava/lang/String;

我找到了多种方法来修复它。尝试添加依赖项：

        <dependency>
            <groupId>javax.annotation</groupId>
            <artifactId>javax.annotation-api</artifactId>
            <version>1.3.2</version>
        </dependency>

尝试添加扩展名：

   <extensions>
        <extension>
            <groupId>javax.annotation</groupId>
            <artifactId>javax.annotation-api</artifactId>
            <version>1.3.2</version>
        </extension>
    </extensions>

这些都没有帮助。

这是 maven-compiler-plugin 配置：

    <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>2.5.1</version>
        <configuration>
            <source>1.8</source>
            <target>1.8</target>
            <encoding>UTF-8</encoding>
        </configuration>
    </plugin>

请帮忙寻找解决办法！！

我正在阅读 JDK 11 中的 LinkedHashMap 源代码，我发现了一段死代码（我不确定）

众所周知，LinkedHashMap 使用双向链表来保存所有元素的顺序。它有一个成员叫做 accessOrder

final boolean accessOrder;

默认情况下它是 false，但如果它被设置为 true，每次运行时get，它都会将它到达的元素移动到链表的末尾。这就是函数afterNodeAccess所做的。

//if accessOrder were set as true, after you visit node e, if e is not the end node of the linked list,
//it will move the node to the end of the linkedlist. 
    void afterNodeAccess(Node<K, V> e) {
        LinkedHashMap.Entry<K, V> last;

        if(accessOrder && (last = tail) != e) {

            //if enter `if` ?it indicates that e is not the end of …