Refactoring Java

Why Refactor?

• Improve Legibility

• Improve Maintainability

• Increase Robustness

• Make Code More Reusable

• Clean up the mess inherent in most 1.0 systems

Non-reasons

• Changes that everyone would really like to make, but that are prevented primarily by concern for backwards compatibility

• Not focusing on new features that could be added to the existing Java in a backwards compatible way.

• Not interested in turning Java into a different language.

• The goal is to do the same things better, while building a stronger foundation for future development.

1. Delete all deprecated methods, fields, classes and interfaces

Java 1.4.0 ships with:

• 22 deprecated classes

• 8 deprecated interfaces

• 50 deprecated fields

• Over 300 deprecated methods!

2.Fix incorrect naming conventions

• Color.red, Color.blue, Color.green, etc.

• System.gc()

• InetAddress

3. Eliminate Primitive Data Types

• All types have classes

• All variables are objects

• +, -, *, etc. are predefined similarly to how + is defined now for String objects

• Compiler is responsible for optimization

• Non-overflowing integers?

4. Extend chars to four bytes

• Unicode currently defines over 90,000 characters with more on the way

• Unicode is not a two-byte character set.

5. Fix threads

• Eliminate ThreadGroups

• Delete the unimplemented destroy() method

• Make double and long operations atomic

• Undeprecate stop(), suspend(), and resume() methods, but move them into a different class

• Decouple monitors from objects?

6. Convert file formats to XML

• Preferences Files

• JAR Manifests

• Object Serialization

7. Ditch the AWT

• Two GUI APIs is one too many.

• Two event models is one too many.

8. Rationalize the Collections API

• Some classes are thread-safe (Hashtable, Vector). Some aren't (LinkedList, HashMap).

• Some collections return null when a missing element is requested. Others throw an exception.

9. Redesign I/O

• File system interfaces

• Replace PrintStream with PrintWriter

• readUTF() and writeUTF()

• Encodings for Reader and Writer

• Default Buffering

10. Redesign class loading from scratch, this time with human interface factors in mind

Other Possibilities:

• Replace integer constants with type-safe enums

• Hide confusing and unnecessary classes like StringTokenizer and StreamTokenizer

• Make Cloneable a true mixin interface or perhaps eliminate it completely

• Rename the Math.log() method the Math.ln() method

• True design by contract support

• Make all exceptions runtime exceptions

• Limit objects to a single thread

Evolve or Be Eaten