源码
https://github.com/unofficial-openjdk/openjdk/releases
直接下载特定的版本jdk-11+28
编译环境centos7
unzip jdk11xxx.zip
cd jdk11xxx
#安装文档中描述的外部库要求（External Library Requirements）
yum install -y freetype-devel cups-devel libXtst-devel libXt-devel libXrender-devel libXi-devel alsa-lib-devel libffi-devel
#安装Build Tools Requirements
yum install -y autoconf
#提示缺少unzip，安装之
yum install -y unzip zip
#再次执行./configure提示configure: Could not find a valid Boot JDK. You might be able to fix this by running 'sudo yum install java-1.8.0-openjdk-devel'.
#尝试 yum install -y java-1.8.0-openjdk-devel
#但发现依然各种错误，提示需要10或者11，yum search openjdk-devel只有11
#详细原因参见Boot JDK Requirements
yum install -y java-11-openjdk-devel
#再次执行提示缺少gcc，建议安装开发工具包
yum groupinstall "Development Tools"
#再次执行提示缺少fontconfig
yum install -y fontconfig-devel
chmod 777 configure
./configure
make
编译成功提示：
Stopping sjavac server
Finished building target 'default (exploded-image)' in configuration 'linux-x86_64-normal-server-release'
此时，在jdk11/build/linux-x86_64-normal-server-release目录下，有个jdk目录，这里面就是最新构建的OpenJDK，进入里面的bin目录，再执行命令./java -version
