This article discusses installing Java under Ubuntu Firefox. Given that Firefox does not come with Java, here is a solution to this issue. By default, Firefox does not accompany Java, i.e., it does not come with the software. This means that the user will not be able to run any Java applications on a Firefox platform. This means you have to manually install Java. This article shows how you can achieve this. After installing Java, all programs or applets can be run on it.