Customize tooling_jre with env var

I have a use case where I need tooling_jre to be customizable: https://github.com/redhat-developer/vscode-java/blob/master/src/requirements.ts#L36.

I can't use the embedded ones because I need to use a custom one that has the right certs to work with an internal service. I also can't use java.jdt.ls.java.home because the location of the JRE will depend on which machine it's running on. Also, settings.json doesn't accept env variables.

Is it possible to get tooling_jre from an env var?

首先阅读 src/requirements.ts 第 36 行附近的内容，以了解 tooling_jre 的选择方式，以及当前 embedded-JRE 行为的定义位置。确定环境变量和回退行为，然后验证是否可以针对每台机器自定义 tooling_jre，同时不破坏现有的配置路径。