Mars is the code name for Eclipse 4.5 which was released on June 24, 2015. Mars.1 and Mars.2 are the code names for the Eclipse 4.5.1 and 4.5.2 fix releases. Use this tag for questions which are specific to this Eclipse release, in most cases you should also specify the eclipse tag.
This is in old release of Eclipse.
Official site for Eclipse Mars: https://eclipse.org/mars
Help for Eclipse Mars: https://help.eclipse.org/mars