JDT.LS binary download does not honour VS Code http.proxy setting in corporate networks

src/extension.ts とダウンロードユーティリティから始め、どの HTTP クライアントが JDT.LS のダウンロードを処理しているか、またその agent 設定がどのように渡されるかを特定します。Issue に記載されている VS Code の http 設定と HTTPS_PROXY/HTTP_PROXY の入力を確認します。更新を含むダウンロードが認証済みプロキシ経由で、報告されているサイレントタイムアウトなしに動作すれば完了です。

Problem

On first install (or when the extension downloads a JDT.LS update), the download fails silently in corporate environments that require an authenticated HTTPS proxy. VS Code exposes the proxy via http.proxy and http.proxyAuthorization settings, and also via HTTPS_PROXY / HTTP_PROXY environment variables injected into the extension host. However, the extension's download logic (in src/extension.ts and the download utility) does not read these and passes no proxy configuration to its HTTP client.

Steps to Reproduce

1. In a corporate environment, set:

   "http.proxy": "http://proxy.corp.example.com:8080",
   "http.proxyStrictSSL": false
   

2. Install the extension on a machine that has no prior JDT.LS installation.
3. Open a Java file. The status bar shows "Downloading Java support..." indefinitely.
4. No error appears; the Output → Java channel shows a TCP timeout to download.jboss.org or the GitHub releases CDN.

Expected Behaviour

The extension should detect the proxy from vscode.workspace.getConfiguration('http').get('proxy') or process.env.HTTPS_PROXY and configure its HTTP download agent accordingly (e.g., via https-proxy-agent or equivalent).

Workaround (not acceptable)

Users currently have to pre-download JDT.LS manually, which is not discoverable and breaks on updates.

Proposed Fix

import HttpsProxyAgent from 'https-proxy-agent';
const proxyUrl = vscode.workspace.getConfiguration('http').get<string>('proxy')
  ?? process.env.HTTPS_PROXY ?? process.env.HTTP_PROXY;
const agent = proxyUrl ? new HttpsProxyAgent(proxyUrl) : undefined;
// Pass agent to node-fetch / got / axios download client

Environment

• OS: Windows 11 Enterprise 10.0.26200 (mandatory corporate proxy, no direct internet)
• VS Code: 1.89+
• Extension: redhat.java latest