我安装了几个版本的unbuntu ，好几个都没有openjdk，命令行键入 java -version，没有出现java版本信息，而是出现其他的东西，反正就是说被引用，或者是找不到包
需要自己安装 软件中心 或者 新立得包管理器
lenky@lenky-Aspire-V5-471G:/var/www$ apt-cache search openjdk | grep ^openjdk
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-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)
openjdk-7-source - OpenJDK Development Kit (JDK) source files
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 - OpenJDK Java runtime, using Hotspot JIT
openjdk-6-jre-headless - OpenJDK Java runtime, using Hotspot JIT (headless)
openjdk-6-jre-lib - OpenJDK Java runtime (architecture independent libraries)
openjdk-6-jre-zero - Alternative JVM for OpenJDK, using Zero/Shark
openjdk-6-source - OpenJDK Development Kit (JDK) source files
openjdk-7-jre-zero - Alternative JVM for OpenJDK, using Zero/Shark
挑你自己需要的安装，比如：lenky@lenky-Aspire-V5-471G:/var/www$ sudo apt-get install openjdk-7-jdk