To protect against potential Java vulnerabilities, Firefox asks you to activate Java for each website you visit that uses Java. If you trust the website, you can allow Java to run by clicking on the "Activate Java" message. If there is no visible area to activate Java content in the page, look for the plugin icon in the address bar, then click it and, in the message panel that opens, choose "Allow Now". For more information, see the How to allow Java on trusted sites article.
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