Carnage4Life (Dare Obasanjo) has completed a detailed comparison of C# and Java , outlining the things that are identical, similar, nearly the same, or completely different between the two languages.

Quick Index

1. The More Things Change The More They Stay The Same
   
   This section describes concepts and language features that are almost exactly the
   same in C# and Java.
   
   
   
   1. We Are All Objects
      
   2. Keyword Jumble
      
   3. Of Virtual Machines and Language Runtimes
      
   4. Heap Based Classes and Garbage Collection
      
   5. Arrays Can Be Jagged
      
   6. No Global Methods
      
   7. Interfaces, Yes. Multiple Inheritance, No.
      
   8. Strings Are Immutable
      
   9. Unextendable Classes
      
   10. Throwing and Catching Exceptions
       
   11. Member Initialization at Definition and Static Constructors
       
       
       
   
   
2. The Same But Different
   
   This section describes concepts and language features that differ either only
   in syntax or in some similarly minor manner between C# and Java.
   
   
   
   1. Main Method
      
   2. Inheritance Syntax
      
   3. Run Time Type Identification (is operator)
      
   4. Namespaces
      
   5. Constructors, Destructors and Finalizers
      
   6. Synchronizing Methods and Code Blocks
      
   7. Access Modifiers
      
   8. Reflection
      
   9. Declaring Constants
      
   10. Primitive Types
       
   11. Array Declarations
       
   12. Calling Base Class Constructors and Constructor Chaining
       
       
       
   
   
3. An Ever So Slight Feeling of Dèjà Vu
   
   This section describes concepts and language features that exist in C#
   that are similar to those that exist in Java but with a significant
   difference.
   
   
   
   1. Nested classes
      
   2. Threads and Volatile Members
      
   3. Operator Overloading
      
   4. switch Statement
      
   5. Assemblies
      
   6. Collections
      
   7. goto (no longer considered harmful)
      
   8. Virtual Methods (and final ones too)
      
   9. File I/O
      
   10. Object Serialization
       
   11. Documentation Generation from Source Code Comments
       
   12. Multiple Classes in a Single File
       
   13. Importing Libraries
       
   14. Events
       
   15. Cross Language Interoperability
       
       
       
   
   
4. Now For Something Completely Different
   
   This section describes language features and concepts that exist in C# and
   have no Java counterpart.
   
   
   
   1. Deterministic Object Cleanup
      
   2. Delegates
      
   3. Enumerations
      
   4. Value Types (Structs)
      
   5. Boxing
      
   6. Run Time Type Identification (as operator)
      
   7. foreach Statement
      
   8. Properties
      
   9. Multidimensional Arrays
      
   10. Attributes
   11. Indexers
       
   12. Preprocessor Directives
       
   13. Aliases
       
   14. Runtime Code Generation
       
   15. Pointers and Unsafe Code
       
   16. Pass by Reference
       
   17. Variable Length Parameter Lists
       
   18. Verbatim Strings
       
   19. Overflow Detection
       
   20. Explicit Interface Implementation
       
       
       
   
   
5. Wish You Were Here
   
   This section describes language features and concepts that exist in Java and
   have no C# counterpart.
   
   
   
   1. Checked Exceptions
      
   2. Cross Platform Portability (Write Once, Run Anywhere)
   3. Extensions
      
   4. strictfp
      
   5. Dynamic Class Loading
      
   6. Interfaces That Contain Fields
      
   7. Anonymous Inner Classes
      
      
      
6. Conclusion


7. Resources


8. Acknowledgements