已安装JRE，能否保留JRE同时安装JDK？求专业建议

Absolutely no need to uninstall your existing JRE before setting up the JDK—they can coexist without any issues, and I’ll break down why plus some practical tips to keep everything running smoothly:

• The JDK already includes a full JRE
  Every standard JDK package comes with its own embedded JRE. When you install the JDK, you’re essentially adding a second (feature-complete) JRE alongside your existing standalone one. There’s no conflict here—they’re separate sets of files in different directories.

• You control which runtime gets used by default
  Your system picks which Java runtime to use via environment variables like JAVA_HOME and PATH. If you want to prioritize the JDK’s JRE (for development work), just make sure the JDK’s bin directory is listed before the standalone JRE’s bin directory in your PATH. If you want to keep your existing JRE as the default for regular apps, leave your PATH as is—existing programs will continue to use the JRE they’re configured for.
  To check your current PATH setup:

  • On Windows: Open Command Prompt and run echo %PATH%
  • On Linux/macOS: Open Terminal and run echo $PATH

• Your existing apps won’t break
  Any programs that rely on your standalone JRE will keep working exactly as before, unless you explicitly change their configuration (like hardcoding a JRE path). The JDK installation won’t modify or overwrite your existing JRE files.

• Uninstalling the standalone JRE is optional (and not required now)
  If down the line you decide you don’t need the separate JRE anymore (since the JDK’s JRE can handle everything), you can safely uninstall it. But since you want to avoid deleting existing programs right now, there’s zero pressure to do this—leave it be.

In short: Go ahead and install the JDK without touching your existing JRE. It’s a totally safe, hassle-free process.

内容的提问来源于stack exchange，提问作者titi