Ubuntu 上使用 apt-get 安装 JDK
1. 检视 apt 库都有哪些 jdk 版本
root@Itble:~# apt-cache search java|grep jdk
default-jdk – Standard Java or Java compatible Development Kit
default-jdk-doc – Standard Java or Java compatible Development Kit (documentation)
gcj-4.6-jdk – gcj and classpath development tools for Java(TM)
gcj-jdk – gcj and classpath development tools for Java(TM)
openjdk-6-dbg – Java runtime based on OpenJDK (debugging symbols)
openjdk-6-demo – Java runtime based on OpenJDK (demos and examples)
openjdk-6-doc – OpenJDK Development Kit (JDK) documentation
openjdk-6-jdk – OpenJDK Development Kit (JDK)
openjdk-6-jre-lib – OpenJDK Java runtime (architecture independent libraries)
openjdk-6-source – OpenJDK Development Kit (JDK) source files
openjdk-7-dbg – Java runtime based on OpenJDK (debugging symbols)
openjdk-7-demo – Java runtime based on OpenJDK (demos and examples)
openjdk-7-doc – OpenJDK Development Kit (JDK) documentation
openjdk-7-jdk – OpenJDK Development Kit (JDK)
openjdk-7-source – OpenJDK Development Kit (JDK) source files
uwsgi-plugin-jvm-openjdk-6 – Java plugin for uWSGI (OpenJDK 6)
uwsgi-plugin-jwsgi-openjdk-6 – JWSGI plugin for uWSGI (OpenJDK 6)
openjdk-6-jre – OpenJDK Java runtime, using Hotspot JIT
openjdk-6-jre-headless – OpenJDK Java runtime, using Hotspot JIT (headless)
openjdk-7-jre – OpenJDK Java runtime, using Hotspot JIT
openjdk-7-jre-headless – OpenJDK Java runtime, using Hotspot JIT (headless)
openjdk-7-jre-lib – OpenJDK Java runtime (architecture independent libraries)
2. 选择版本进行安装
root@Itble:~# apt-get install openjdk-7-jdk
3. 设定环境变数
root@Itble:~# vi /etc/profile
新增如下内容：
#set java environment
JAVA_HOME=/usr/lib/jvm/java-1.7.0-openjdk-amd64
JRE_HOME=$JAVA_HOME/jre
CLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin
export JAVA_HOME JRE_HOME CLASS_PATH PATH
让修改生效：
root@Itble:~# source /etc/profile
4. 验证
root@Itble:~# java -version
java version “1.7.0_79”
OpenJDK Runtime Environment (IcedTea 2.5.5) (7u79-2.5.5-0ubuntu0.12.04.1)
OpenJDK 64-Bit Server VM (build 24.79-b02, mixed mode)