Shiraz Khan wrote:...still in development...code of one of classes has exceeded more than 110,000 lines. ...
We don't want to move any methods to a new class, as it will impact the whole application and there will be lots of code changes.
Eclipse is the least of your problems. Have you considered what a nightmare it is going to be to maintain that code in the future?
I do not mean to offend you, but if our class has these many lines, do yourself a favor, stop coding and return to the drawing board. You need to start with a proper modular design, split into multiple classes, based on logical functionality.
Usually, the rule of the thumb is a class does not
ideally exceed ~2000-2500 lines. Of course the actual number can be debatable, but it definitely should not be as high as yours.
Ok. Enough of my cribbing

Coming back to your problem.
Easiest and quickest way to fix your problem would be to provide pass through methods in your lumpy class.
Say your lumpy class contains 100 methods with an average of say 20 lines in each method.
Break these 100 methods into multiple classes and transfer the methods in those classes.
In your lumpy class, provide pass through methods which will in turn invoke these distributed methods. That way, the code which invokes the methods in the lumpy class need not be changed. This should ensure minimum code changes.