系统需求

• 宿主机操作系统：Windows 11 专业工作站版
• 虚拟机软件：VMware® Workstation 16 Pro
• 虚拟机操作系统：ubuntu-22.04.2-desktop-amd64

更换ubuntu源

💡 Tips：这里使用的是清华大学开源软件镜像站

# 备份/etc/apt/sources.list后，将该文件替换为下面内容
sudo vi /etc/apt/sources.list
# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ jammy main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ jammy main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ jammy-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ jammy-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ jammy-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ jammy-backports main restricted universe multiverse

# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ jammy-security main restricted universe multiverse
# # deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ jammy-security main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu/ jammy-security main restricted universe multiverse
# deb-src http://security.ubuntu.com/ubuntu/ jammy-security main restricted universe multiverse

# 预发布软件源，不建议启用
# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ jammy-proposed main restricted universe multiverse
# # deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ jammy-proposed main restricted universe multiverse

更新软件源

sudo apt update

获取源码
----

> 💡 Tips：在国内推荐使用zip包方式下载，比起从Mercurial复制一堆零散文件要快非常多

方式一：下载源码zip包，[https://hg.openjdk.org/jdk/jdk12/archive/06222165c35f.zip](https://hg.openjdk.org/jdk/jdk12/archive/06222165c35f.zip)  
方式二：hg clone https://hg.openjdk.java.net/jdk/jdk12

构建基础编译环境
--------

> 💡 Tips：基础编译工具，例如gcc，g++，make等

sudo apt install build-essential

上面命令安装的gcc,g版本为11，但是openjdk12需要版本7，所以需要安装低版本gcc，g

ubuntu软件源配置文件

sudo vi /etc/apt/sources.list

向文件中添加如下代码,追加一个软件源,推荐国内镜像，官方镜像速度很慢

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main universe

网上一般提供的是官方镜像，比较慢

deb [arch=amd64] http://archive.ubuntu.com/ubuntu focal main universe

更新源文件

sudo apt update

安装 gcc-7 g+±7

sudo apt install gcc-7
sudo apt install g+±7

多版本管理 最后的数字越大，优先级越高 这里维护了7 11两个个版本 默认是版本7

sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 50
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-11 30

sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g+±7 50
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g+±11 30

查看当前gcc,g++版本

sudo gcc --version
sudo g++ --version

安装其他依赖
------

> 💡 Tips：这些依赖都是执行bash configure后提示缺少的依赖

bash configure
configure: error: Could not find fontconfig! You might be able to fix this by running ‘sudo apt-get install libfontconfig1-dev’.
configure exiting with result code 1

sudo apt install -y libfreetype6-dev
sudo apt install -y libcups2-dev
sudo apt install -y libx11-dev libxext-dev libxrender-dev libxrandr-dev libxtst-dev libxt-dev
sudo apt install -y libasound2-dev
sudo apt install -y libffi-dev
sudo apt install -y autoconf
sudo apt install -y libfontconfig1-dev

```

安装Bootstrap JDK
---------------

其中一部分（HotSpot）代码使用C、C++编写，而更多的代码则是使用Java语言来实现，因此编译这些Java代  
码就需要用到另一个编译期可用的JDK

```
sudo apt install openjdk-11-jdk

```

进行编译
----

```
# 编译FastDebug版、仅含Server模式的HotSpot虚拟机
bash configure --enable-debug --with-jvm-variants=server

```

顺利的话会出现如下内容

```
A new configuration has been successfully created in
/home/damimg/Downloads/jdk12-06222165c35f/build/linux-x86_64-server-release
using default settings.

Configuration summary:
* Debug level:    release
* HS debug level: product
* JVM variants:   server
* JVM features:   server: 'aot cds cmsgc compiler1 compiler2 epsilongc g1gc graal jfr jni-check jvmci jvmti management nmt parallelgc serialgc services shenandoahgc vm-structs zgc' 
* OpenJDK target: OS: linux, CPU architecture: x86, address length: 64
* Version string: 12-internal+0-adhoc.damimg.jdk12-06222165c35f (12-internal)

Tools summary:
* Boot JDK:       openjdk version "11.0.18" 2023-01-17 OpenJDK Runtime Environment (build 11.0.18+10-post-Ubuntu-0ubuntu122.04) OpenJDK 64-Bit Server VM (build 11.0.18+10-post-Ubuntu-0ubuntu122.04, mixed mode, sharing)  (at /usr/lib/jvm/java-11-openjdk-amd64)
* Toolchain:      gcc (GNU Compiler Collection)
* C Compiler:     Version 7.5.0 (at /usr/bin/gcc)
* C++ Compiler:   Version 7.5.0 (at /usr/bin/g++)

Build performance summary:
* Cores to use:   1
* Memory limit:   1940 MB

```

开始编译
----

```
make images

```

> 💡 Tips：笔者在这一步，不顺利，遇到了异常，后来发现为jdk12对make4.3的支持不够，jdk15修复了，原文：[https://github.com/openjdk/panama-foreign/commit/af5c725b](https://github.com/openjdk/panama-foreign/commit/af5c725b)

```
Building target 'images' in configuration 'linux-x86_64-server-release'
gmake[3]: *** No rule to make target '/home/damimg/Downloads/jdk12-06222165c35f/build/linux-x86_64-server-release/buildtools/langtools_tools_classes/_the.BUILD_TOOLS_LANGTOOLS.vardeps', needed by '/home/damimg/Downloads/jdk12-06222165c35f/build/linux-x86_64-server-release/buildtools/langtools_tools_classes/_the.BUILD_TOOLS_LANGTOOLS_batch'.  Stop.
gmake[2]: *** [make/Main.gmk:73: buildtools-langtools] Error 2

ERROR: Build failed for target 'images' in configuration 'linux-x86_64-server-release' (exit code 2) 

No indication of failed target found.
Hint: Try searching the build log for '] Error'.
Hint: See doc/building.html#troubleshooting for assistance.

make[1]: *** [/home/damimg/Downloads/jdk12-06222165c35f/make/Init.gmk:310: main] Error 2
make: *** [/home/damimg/Downloads/jdk12-06222165c35f/make/Init.gmk:186: images] Error 2

```

修改MakeBase.gmk
--------------

修改之前（make/common/MakeBase.gmk）

```
# Param 2 - (optional) name of file to store value in
DependOnVariableHelper = \
    $(strip \
        $(eval -include $(call DependOnVariableFileName, $1, $2)) \
        $(if $(call equals, $(strip $($1)), $(strip $($1_old))),,\
          $(call MakeDir, $(dir $(call DependOnVariableFileName, $1, $2))) \
          $(if $(findstring $(LOG_LEVEL), trace), \
              $(info NewVariable $1: >$(strip $($1))<) \
              $(info OldVariable $1: >$(strip $($1_old))<)) \
          $(call WriteFile, $1_old:=$(call DoubleDollar,$(call EscapeHash,$($1))), \
              $(call DependOnVariableFileName, $1, $2))) \
        $(call DependOnVariableFileName, $1, $2) \
    )

# Main macro

```

修改之后

```
# Param 2 - (optional) name of file to store value in
DependOnVariableHelper = \
    $(strip \
        $(eval $1_filename := $(call DependOnVariableFileName, $1, $2)) \
        $(if $(wildcard $($1_filename)), $(eval include $($1_filename))) \
        $(if $(call equals, $(strip $($1)), $(strip $($1_old))),,\
          $(call MakeDir, $(dir $($1_filename))) \
          $(if $(findstring $(LOG_LEVEL), trace), \
              $(info NewVariable $1: >$(strip $($1))<) \
              $(info OldVariable $1: >$(strip $($1_old))<)) \
          $(call WriteFile, $1_old:=$(call DoubleDollar,$(call EscapeHash,$($1))), \
              $($1_filename))) \
        $($1_filename) \
    )

# Main macro

```

再次编译
----

顺利话会得到如下内容

```
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: /home/damimg/Downloads/jdk12-06222165c35f/src/demo/share/jfc/TableExample/TableExample4.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Creating support/demos/image/jfc/TableExample/TableExample.jar
Updating support/demos/image/jfc/TableExample/src.zip
Compiling 1 files for BUILD_DEMO_TransparentRuler
Creating support/demos/image/jfc/TransparentRuler/TransparentRuler.jar
Updating support/demos/image/jfc/TransparentRuler/src.zip
Warning: No SCM configuration present and no .src-rev
Creating jdk image
Creating CDS archive for jdk image
Updating images/sec-bin.zip
Stopping sjavac server
Finished building target 'images' in configuration 'linux-x86_64-server-release'

```

验证编译结果
------

```
./build/linux-x86_64-server-release/jdk/bin/java --version


```

成功的话，会输出以下内容

```
openjdk 12-internal 2019-03-19
OpenJDK Runtime Environment (build 12-internal+0-adhoc.damimg.jdk12-06222165c35f)
OpenJDK 64-Bit Server VM (build 12-internal+0-adhoc.damimg.jdk12-06222165c35f, mixed mode)

```