The document discusses various refactoring techniques organized into categories including composing methods, moving features between objects, organizing data, simplifying conditional expressions, simplifying method calls, and dealing with generalization. Some specific techniques mentioned are extract method, move method, encapsulate field, replace nested conditional with guard clauses, add parameter, and form template method. The goal of refactoring is to improve the design of existing code through techniques like extracting duplicate code or conditional logic, simplifying interfaces, and managing dependencies between code elements.

1. Refactoring Techniques
Composing Methods
Extract Method
Inline Method
Extract Variable
Inline Temp

2. Replace Temp with Query
Replace Method with Method Object
Split Temporary Variable

3. Remove Assignments to Parameters
Substitute Algorithm

4. Moving Features between Objects
Move Method
Move Field
Extract Class
Inline Class

5. Hide Delegate
Remove Middleman
Introduce Foreign Method

6. Introduce Local Extension

7. Organizing Data
Self-Encapsulate Field
Encapsulate Field
Change Value to Reference
Change Reference to Value

8. Replace Data Value with Object
Replace Array with Object
Encapsulate Collection
Change Unidirectional Association to Bidirectional
Change Bidirectional Association to Unidirectional
Replace Magic Number with Symbolic Constant

9. Duplicate Observed Data
Replace Type Code with Class
Replace Type Code with Subclasses

10. Replace Type Code with State/Strategy
Replace Subclass with Fields

11. Simplifying Conditional Expressions
Decompose Conditional
Consolidate Conditional Expression
Consolidate Duplicate Conditional Fragments
Remove Control Flag

12. Replace Nested Conditional with Guard Clauses
Introduce Assertion

13. Replace Conditional with Polymorphism
Introduce Null Object

14. Simplifying Method Calls
Rename Method
Add Parameter
Remove Unused Parameter
Separate Query from Modifier
Parameterize Method
Preserve Whole Object
Replace Parameter with Method Call

15. Replace Parameter with Explicit Methods
Introduce Parameter Object
Remove Setting Method for Immutable Fields
Hide Method that should not be Public

16. Replace Constructor with Factory Method
Replace Error Code with Exception
Replace Exception with Test

17. Dealing with Generalization
Pull Up Field
Pull Up Method
Pull Up Constructor Body
Push Down Field

18. Push Down Method
Extract Subclass
Extract Superclass
Collapse Hierarchy

19. Extract Interface
Form Template Method
Replace Inheritance with Delegation
Replace Delegation with Inheritance