Updating checksyle.xml

Progress on http://forum.astrogrid.org/read.php?TID=643

Rules in Elements of Java Style not in checkstyle.xml

Rules in Elements of Java Style to throw out

Rules in checkstyle.xml (not in EJS) worth keeping

• Hide Utility Class ctor: classes containing only static methods should not have a public or default ctor
• Checks that a class which has only private constructors is declared as final.
• Redundant modifier (e.g. use of public within an interface)

Rules in checkstyle.xml (not in EJS) to demote to info level

• Checks that the order of modifiers conforms to the suggestions in the Java Language specification, sections 8.1.1, 8.3.1 and 8.4.3. The correct order is: public, protected, private, abstract, static, final, transient, volatile, synchronized, native, strictfp.
• Avoid inline conditionals (in fact, should we just ignore these?)
• Checks that local variables that never have their values changed are declared final. The check can be configured to also check that unchanged parameters are declared final.
• Declaration order check
• Explicit initialisation of member variables: Checks if any class or object member explicitly initialized to default for its type value (null for object references, zero for numeric types and char and false for booolean.
• Nested ifs (only 2 levels allowed)

Rules in EJS we cannot enforce with checkstyle

• #81 - don't call nonfinal methods from within a constructor (caught me several times this one - if a subclass overrides the method, then the method can end up working on a partially initialised class. Subtle, and difficult to reproduce).