Eclipse: Most useful refactorings [closed]

Answer 1

What I use the most is Rename, Extract Method and Change Method Signature, in that order.

Answer 2

My favourites (in order of using):

1. Rename (Alt-Shift-R, or Ctrl-1 for faster in-file renaming)
   Good renaming variables,methods,etc. without side effects.
2. Extract Variable (Ctrl-1, Alt-Shift-L)
   Good for splitting a quick-made-100-character-line to separate steps.
3. Extract Method (Alt-Shift-M)
   Create a method out of some code without any side effects.
4. Split Variable Declaration (Ctrl-1)
   Good when you initialize a variable at the declaration and now find out, that the initialisation needs to be in a try- or if-block.
5. Change Method Signature (Alt-Shift-C)
   The handy Swiss Army Knife of method signature manipulation, including default values for new parameters.
6. Pull Up/Push Down Pull methods and variables to a generic interface or superclass or push it down to a subclass
7. Extract Interface/Superclass
   Extract an interface or a superclass out of the current class. Very handy.

Answer 3

CTRL + 1 on a red lined section, i.e. quick fix.

Answer 4

I use :

1- Rename - to correct better method name

2- Move - to organize my package in better ways, like when I start my project, it was so small so no need of a io package, but now yes.

3- Generate Comments -when I create a .class avoid me to re-copy the GPL license, etc

4- Correct Indentation - to keep my code readable.

Answer 5

It's also worth reading this research: How do API evolve? A story of refactoring. by D. Dig and R. Johnson.

The authors noticed that 80% of the changes were refactorings and classified them. Here is the abstract:

Frameworks and libraries change their APIs. Migrating an application to the new API is tedious and disrupts the development process. Although some tools and ideas have been proposed to solve the evolution of APIs, most updates are done manually. To better understand the requirements for migration tools, we studied the API changes of four frameworks and one library. We discovered that the changes that break existing applications are not random, but tend to fall into particular categories. Over 80% of these changes are refactorings. This suggests that refactoring-based migration tools should be used to update applications.

Answer 6

I like the Extract Method (Alt+Shift+M), and since 3.6M1, it now handles selections that contain continue statements.

To preserve the semantics of the existing code, the selection needs to include the last statement of the loop. In the extracted method, continue statements are changed to return:

Extract method refactoring with continue http://download.eclipse.org/eclipse/downloads/drops/S-3.6M1-200908061400/images/extract-method-continue.png

For a selection that would need multiple return values in the extracted method, Eclipse now lists the conflicting variables in the error message:

Extract method refactoring with an ambiguous return value error http://download.eclipse.org/eclipse/downloads/drops/S-3.6M1-200908061400/images/extract-method-multiple-return-values.png