Adding a separator to the Eclipse Outline view (like #pragma mark)

You can use "Add Bookmark".

One way to do that is to right-click on the left side (where line numbers are shown), and select "Add Bookmark...".

You can view them in "Bookmarks" view.

Eclipse outline view supports categories (with @category in javadoc) for showing additional information on methods. See the following screenshots for an example of such usage.

Unfortunately grouping by categories has not been implemented yet. There is an open feature request for this, but it is nearly four years old and clearly stated that it needs community effort. Personally I do not know such plugin.

The horror:

@SuppressWarnings("unused")
private int _______________________________________;

Or if you prefer labels:

@SuppressWarnings("unused")
private int _______________Lifecycle_______________;

Bonus points for varying the number of underscores so you can have many separator lines.

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My Android Studio Version

Use code regions:

//region

    ... your code here ... 

//endregion

Bonus points for making the folded presentation look like a comment:

//
//region // Lifecycle

   ... your code here ...

//endregion
//