OpenJDK 8：无法解析主机名

Question

我正在尝试运行 slf4j 在 openJDK 8 上使用 log4j 2.8（Ubuntu 8u131-b11-0ubuntu1.17.04.1 上的最新版本）。

当运行ning simple java class 通过 maven openjdk 无法解析本地主机名时：

  Exception in thread "AWT-EventQueue-0" java.lang.NoSuchFieldError: preferIPv6Address
    at java.base/java.net.InetAddress.init(Native Method)
    at java.base/java.net.InetAddress.init(Native Method)
    at java.base/java.net.InetAddress.<clinit>(InetAddress.java:333)
    at org.apache.logging.log4j.core.util.NetUtils.getLocalHostname(NetUtils.java:53)
    at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:539)
    at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:617)
    at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:634)
    at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:229)
    at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:152)
    at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45)
    at org.apache.logging.log4j.LogManager.getContext(LogManager.java:194)
    at org.apache.logging.log4j.spi.AbstractLoggerAdapter.getContext(AbstractLoggerAdapter.java:122)
    at org.apache.logging.slf4j.Log4jLoggerFactory.getContext(Log4jLoggerFactory.java:43)
    at org.apache.logging.log4j.spi.AbstractLoggerAdapter.getLogger(AbstractLoggerAdapter.java:46)
    at org.apache.logging.slf4j.Log4jLoggerFactory.getLogger(Log4jLoggerFactory.java:29)
    at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:358)
    at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:383)

看起来像方法

public static InetAddress getLocalHost() throws UnknownHostException

的实现方式与 Oracle java 不同。

/etc/hosts 包含 ipv6 记录：

::1     ip6-localhost ip6-loopback

Answer 1

问题是系统安装了JDK9引起的。 Log4j 2.8 与 Java 9 尚不兼容。

删除 JDK9 或将首选项设置为 JDK8 应该可以解决问题。在 Debian 上：

sudo update-alternatives --config java

OpenJDK 8：无法解析主机名

OpenJDK 8: can't resolve hostname

java

openjdk

java-8