Linux下Firefox运行Java：SiteScope插件缺失问题求助（Oracle JRE）

Hey there! Let's work through this issue together. Since you've already got Oracle JRE installed, the problem almost certainly ties back to Firefox's restricted support for Java plugins (which use the NPAPI framework) in newer versions. Here's how to get things working:

1. Check Firefox's NPAPI Support Status #

Starting with Firefox 52, the browser disables most NPAPI plugins by default (Java falls into this category). First, confirm your Firefox version:

• Type about:support into the address bar and look for the "Version" field. If it's 52 or newer, we'll need to re-enable NPAPI.

2. Enable NPAPI in Firefox #

Follow these steps to turn on NPAPI support:

• Open Firefox and type about:config into the address bar. Click "Accept the Risk and Continue" when prompted.
• Use the search bar to find plugin.load_flash_only — double-click it to set its value to false.
• Next, search for dom.ipc.plugins.enabled.java. If it exists, double-click to ensure it's set to true. If it doesn't exist:
  • Right-click anywhere in the config list, hover over "New", then select "Boolean".
  • Name the new preference dom.ipc.plugins.enabled.java and set its value to true.
• Restart Firefox to apply these changes.

3. Verify the Java Plugin is Recognized #

Now check if Firefox sees your Oracle JRE plugin:

• Type about:addons into the address bar, then click "Plugins" in the left menu (older Firefox versions might use about:plugins instead).
• Look for an entry named "Oracle Java(TM) Plugin" or similar. If it shows up, you're halfway there!
• If you don't see it, we'll need to link the plugin file manually.

4. Manually Link the Java Plugin to Firefox #

Oracle JRE includes the browser plugin file libnpjp2.so, but Firefox might not be picking it up automatically. Let's fix that:

• First, find your Oracle JRE installation path. Common locations are:
  • System-wide install: /usr/lib/jvm/java-[your-jre-version]-oracle
  • User-specific install: $HOME/jre-[your-jre-version]
• Navigate to the plugin directory inside your JRE:
  • For 64-bit systems: [jre-path]/lib/amd64/
  • For 32-bit systems: [jre-path]/lib/i386/
• Create a symbolic link to Firefox's plugin directory:
  • For user-specific setup (no sudo needed):

    ln -s /path/to/jre/lib/amd64/libnpjp2.so ~/.mozilla/plugins/
    

  • For system-wide setup (requires sudo):

    sudo ln -s /path/to/jre/lib/amd64/libnpjp2.so /usr/lib/mozilla/plugins/
    

• Restart Firefox and check the plugins list again — the Java plugin should now appear.

5. Confirm SiteScope Compatibility #

Finally, make sure your SiteScope version is compatible with both your installed Oracle JRE version and Firefox version. Some older SiteScope releases require specific Java versions (e.g., Java 8), so double-check the SiteScope documentation if you still run into issues.

内容的提问来源于stack exchange，提问作者user273695