有没有办法更新所有与 Java 相关的替代品？

Question

有没有办法使用 快速切换所有与 Java 相关的替代方案update-alternatives？

例如，如果想将 Java 切换到 7，我运行sudo update-alternatives --config java并选择 Java 7 OpenJdk。但如果我跑update-alternatives --get-selections | grep java我得到以下，

appletviewer                   auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/appletviewer
extcheck                       auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/extcheck
idlj                           auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/idlj
itweb-settings                 auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/itweb-settings
jar                            auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jar
jarsigner                      auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jarsigner
java                           manual   /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java
javac                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/javac
javadoc                        auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/javadoc
javah                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/javah
javap                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/javap
javaws                         auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/javaws
jconsole                       auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jconsole
jdb                            auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jdb
jexec                          auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/lib/jexec
jhat                           auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jhat
jinfo                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jinfo
jmap                           auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jmap
jps                            auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jps
jrunscript                     auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jrunscript
jsadebugd                      auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jsadebugd
jstack                         auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jstack
jstat                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jstat
jstatd                         auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jstatd
keytool                        auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/keytool
native2ascii                   auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/native2ascii
orbd                           auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/orbd
pack200                        auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/pack200
policytool                     auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/policytool
rmic                           auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/rmic
rmid                           auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/rmid
rmiregistry                    auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/rmiregistry
schemagen                      auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/schemagen
serialver                      auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/serialver
servertool                     auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/servertool
tnameserv                      auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/tnameserv
unpack200                      auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/unpack200
wsgen                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/wsgen
wsimport                       auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/wsimport
xjc                            auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/xjc

如您所见，我的 Java 替代方案已切换到 7，但所有其他基于 OpenJDK 6 的替代方案均未切换。当然，我可以手动切换每一个或编写一个脚本来执行此操作，但我认为有更好的方法来完成此操作。

Answer 1

诀窍是使用update-java-alternatives（从java-common包中）。

所以为了使用 OpenJDK 6 到 7，我曾经update-java-alternatives -l得到一个 Java 替代品列表，然后习惯于sudo update-java-alternatives -s java-1.7.0-openjdk-amd64JDK。

注意：上面的命令抛出了以下错误，

update-alternatives: error: no alternatives for mozilla-javaplugin.so.
update-java-alternatives: plugin alternative does not exist: /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so

这是因为默认情况下未安装 openjdk 插件。修复运行

sudo apt-get install icedtea-7-plugin

并重新运行update-java-alternatives。