Install sonarlint plugin in eclipse offline

From another post...

1. Download your plugin
2. Open Eclipse
3. From the menu choose: Help / Install New Software...
4. Click the Add button
5. In the Add Repository dialog that appears, click the Archive button next to the Location field
6. Select your plugin file, click OK

You could also just copy plugins to the eclipse/plugins directory, but it's not recommended.

For offline installation and older versions see the update site archive at https://bintray.com/sonarsource/SonarLint-for-Eclipse/releases