OpenSUSE下安装JDK
openSUSE自带了OpenJDK，安装Oracle JDK后，需要使用alternatives切换系统默认使用的JDK版本。
1）安装JDK：
linuxidc@linux-linuxidc:~/下载> sudo zypper install jdk-8u66-linux-x64.rpm -y
...
/var/tmp/rpm-tmp.DfGrcZ: line 638: /usr/sbin/alternatives: No such file or directory
/var/tmp/rpm-tmp.DfGrcZ: line 650: /usr/sbin/alternatives: No such file or directory
warning: %post(jdk1.8.0_66-2000:1.8.0_66-fcs.x86_64) scriptlet failed, exit status 127
有如上的报错，“/usr/sbin/alternatives”这个文件找不到。openSUSE相应的文件名是update-alternatives，尝试做了软连接，会报新的错误：
update-alternatives: error: alternative javaws can't be slave of java: it is a slave of javaplugin
update-alternatives: error: alternative javaws can't be slave of javac: it is a slave of javaplugin
warning: %post(jdk1.8.0_66-2000:1.8.0_66-fcs.x86_64) scriptlet failed, exit status 2
看来openSUSE和Oracle JDK不是很友好啊，需要手动完成后续的必要步骤（从网上找的，可能不是安装脚本的全部后续操作）。
2）用alternatives声明jdk版本并设为默认：
linuxidc@linux-linuxidc:~/下载> sudo /usr/sbin/update-alternatives --install "/usr/bin/java" "java" "/usr/java/jdk1.8.0_66/bin/java" 40
linuxidc@linux-linuxidc:~/下载> sudo /usr/sbin/update-alternatives --install "/usr/lib64/browser-plugins/javaplugin.so" "javaplugin" "/usr/java/jdk1.8.0_66/jre/lib/amd64/libnpjp2.so" 40
——其中红色部分根据操作系统及指令集不同会有不同。
linuxidc@linux-linuxidc:~/下载> sudo /usr/sbin/update-alternatives --config java
There are 3 choices for the alternative java (providing /usr/bin/java).
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/lib64/jvm/jre-1.8.0-openjdk/bin/java 18040 auto mode
1 /usr/java/jdk1.8.0_66/bin/java 40 manual mode
2 /usr/lib64/jvm/jre-1.7.0-openjdk/bin/java 17147 manual mode
3 /usr/lib64/jvm/jre-1.8.0-openjdk/bin/java 18040 manual mode
Press enter to keep the current choice[*], or type selection number: 1
update-alternatives: using /usr/java/jdk1.8.0_66/bin/java to provide /usr/bin/java (java) in manual mode
linuxidc@linux-linuxidc:~/下载> sudo /usr/sbin/update-alternatives --config javaplugin
There are 3 choices for the alternative javaplugin (providing /usr/lib64/browser-plugins/javaplugin.so).
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/lib64/java-1_8_0-openjdk-plugin/lib/IcedTeaPlugin.so 18020 auto mode
1 /usr/java/jdk1.8.0_66/jre/lib/amd64/libnpjp2.so 40 manual mode
2 /usr/lib64/java-1_7_0-openjdk-plugin/lib/IcedTeaPlugin.so 17147 manual mode
3 /usr/lib64/java-1_8_0-openjdk-plugin/lib/IcedTeaPlugin.so 18020 manual mode
Press enter to keep the current choice[*], or type selection number: 1
update-alternatives: using /usr/java/jdk1.8.0_66/jre/lib/amd64/libnpjp2.so to provide /usr/lib64/browser-plugins/javaplugin.so (javaplugin) in manual mode
3）查看JDK版本：
linuxidc@linux-linuxidc:~/下载> java -version
java version "1.8.0_66"
4）修改JAVA_HOME:
但是此时JAVA_HOME尚不正确：
linuxidc@linux-linuxidc:~/下载> echo $JAVA_HOME
/usr/lib64/jvm/jre
修改/etc/profile文件，在文件尾追加：
export JAVA_HOME=/usr/java/jdk1.8.0_66
export JRE_HOME=$JAVA_HOME/jre
export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib:$CLASSPATH
export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH
退出，重新登陆后：
linuxidc@linux-linuxidc:~> echo $JAVA_HOME
/usr/java/jdk1.8.0_66
DONE！