终端执行：sudo apt-get install openjdk-8-jdk -y

也是无法定位

先执行 sudo apt-get update 再执行 sudo apt-get install openjdk-8-jdk -y 看看。不行就把输出贴出来。

1. 下载Sun版JDK压缩包（.tar.gz），选择其中的32/64位Linux版本。
2. 将其解压缩：sudo tar -zxvf ~/Downloads/jdk-8u45-linux-i586.tar.gz -C /usr/lib 中参数-C后面的路径是解压缩的目标路径。
3.sudo update-alternatives --install /usr/bin/java java /opt/jdk1.8.0_66/bin/java 1000
sudo update-alternatives --install /usr/bin/javac javac /opt/jdk1.8.0_66/bin/javac 1000

参考官网：
Starting with version 8u40, the JDK installation is integrated with the alternatives framework and after installation, the alternatives framework is updated to reflect the binaries from the recently installed JDK. Java commands such as java, javac, javadoc, and javap can be invoked from the command line.