java - 从源代码构建 Elasticsearch，但它需要 Java 10

Question

我正在尝试从源代码构建 Elasticsearch。我从 GitHub repo 克隆而来今天，我按照“Building from Source”下的说明进行操作。

运行 ./gradlew assemble 产生以下错误:

...
> Configure project :benchmarks
=======================================
Elasticsearch Build Hamster says Hello!
=======================================
  Gradle Version        : 4.7
  OS Info               : Linux 4.4.0-112-generic (amd64)
  JDK Version           : Oracle Corporation 1.8.0_161 [Java HotSpot(TM) 64-Bit Server VM 25.161-b12]
  JAVA_HOME             : /usr/lib/jvm/java-8-oracle
  Random Testing Seed   : 5554B47DBBCF3CFB
Project evaluation failed including an error in afterEvaluate {}. Run with --stacktrace for details of the afterEvaluate {} error.

FAILURE: Build failed with an exception.

* Where:
Build file '<redacted>/elasticsearch-master/benchmarks/build.gradle' line: 31

* What went wrong:
A problem occurred evaluating project ':benchmarks'.
> Failed to apply plugin [id 'elasticsearch.build']
   > the environment variable JAVA_HOME must be set to a JDK installation directory for Java 1.10 but is [/usr/lib/jvm/java-8-oracle] corresponding to [1.8]
...

运行 sudo ./gradlew assemble 会产生不同的错误:

FAILURE: Build failed with an exception.

* Where:
Build file '<redacted>/elasticsearch-master/benchmarks/build.gradle' line: 31

* What went wrong:
A problem occurred evaluating project ':benchmarks'.
> Failed to apply plugin [id 'elasticsearch.build']
   > JAVA_HOME must be set to build Elasticsearch

但据我所知，我的 JAVA_HOME 已设置:

$ echo $JAVA_HOME
/usr/lib/jvm/java-8-oracle

$ sudo echo $JAVA_HOME
/usr/lib/jvm/java-8-oracle

$ ls /usr/lib/jvm/java-8-oracle
bin  COPYRIGHT  db  include  javafx-src.zip  jre  lib  LICENSE  man  README.html  release  src.zip  THIRDPARTYLICENSEREADME-JAVAFX.txt  THIRDPARTYLICENSEREADME.txt

其他可能有用的信息:

$ java -version
java version "1.8.0_161"
Java(TM) SE Runtime Environment (build 1.8.0_161-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.161-b12, mixed mode)

$ gradle -v

------------------------------------------------------------
Gradle 4.7
------------------------------------------------------------

Build time:   2018-04-18 09:09:12 UTC
Revision:     b9a962bf70638332300e7f810689cb2febbd4a6c

Groovy:       2.4.12
Ant:          Apache Ant(TM) version 1.9.9 compiled on February 2 2017
JVM:          1.8.0_161 (Oracle Corporation 25.161-b12)
OS:           Linux 4.4.0-112-generic amd64

我正在运行 Ubuntu 16.04。

有谁知道如何在不升级到 Java 10 的情况下修复此错误(或者，我如何从源代码构建最新版本的 Elasticsearch)？

Answer 1

当 Elasticsearch says that it only requires Java 8 ，这实际上意味着 Java 8 足以运行 Elasticsearch。 构建 Elasticsearch 完全不同，似乎需要 Java 10(我假设正在使用 Java 10 功能)。因此，如果您想从源代码构建 Elasticsearch，则必须升级到 Java 10。