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?

まず src/requirements.ts の36行目付近を読み、tooling_jre がどのように選択され、現在の embedded-JRE の動作がどこで定義されているかを理解します。環境変数とフォールバック動作を特定し、既存の設定パスを壊すことなく tooling_jre をマシンごとにカスタマイズできることを確認します。