The Ghost In The Machine said:
[W] int vs. Integer, float vs. Float, boolean vs. Boolean. Boxing helps
but is a band-aid.
C# got autoboxing around the same time as Java.
[?] Are the non-byte datatypes fixed-size?
Yes; a char is ALWAYS unsigned 16 bits, an int is ALWAYS signed 32
bits amd a long is ALWAYS signed 64 bits. float and double also have
set sizes.
[P] The Enumerator/Iterator dichotomy doesn't look necessary.
I never understood why Sun half-assed introduced some patterns to
early Java (Observer and Iterator in particular) - and then managed to
call their Iterator class Enumerator instead.
[W] AWT and Swing work well enough together but do we really need both?
Swing builds on AWT. The former feels half-assed, and to do much you
end up using the primitice stuff like Graphics anyway, which is what
Swing basically does: It renders in the Graphics of one of the root
peers.
[W] [].length vs. String.length() vs. Collection.size(). Can we
clean this up?
Nope.
[W] a.equals(b) requires that a be non-null.
Clarification: "object-reference dot-operator something" requires
object-reference to be non-null since it's the type of the object that
defines what exact method is called. Without an object there is no way
to know - and code is easier to write if an instance method can be
certain "this" is non-null.
[W] "".equals(null) returns false. Granted, maybe they're supposed
to be unequal, but one wonders if there shouldn't be an
equalsNullIsEmpty(), at least, ugly as that is. Most people ensure
Strings are non-null so this isn't that big a deal but it is
annoying.
An empty String and null are distinct. That you want to equate them is
not the language's problem (which defines a very narrow role for
null); You want special semantics, you need to code them yourself.
[W] Various protocols in J2EE assume a mapping of xzy -> getXyz, setXyz.
Yes, that's the JavaBean specification.
Unfortunately, class is a reserved keyword, although getClass() exists.
Why would you ever want to use getClass() for something else? It has a
particular meaning in the language.
In a way, that's good news, as that means getClass() isn't available
for the casual user and he would have to use things such as
getDefiningClass(), getClazz(), or other such junk.
In a context where you want a property called "class", use an alias
like "course", "socialLadderRung" or whatever.
[?] I'm not sure about catching run-time exceptions such as
NullPointerException and IllegalArgumentException. It's convenient
to catch them, of course, print the traceback, and keep the app from
dying. However, it also is probably being misused. How to prevent
this, I for one don't know; I doubt C# has a much better solution
here, and I certainly do not.
C#'s "solution" is to make all exceptions RuntimeExceptions.
For
NPE, you really should test for null instead.
[P] java.io.Serializable should have generated XML from the
beginning.
No, because a binary representation is more compact.
Of course there's the little issue of timing;
I don't think Java, in its alpha stages, knew about XML.
It wasn't as popular back then compared with e.g. EDIFACT
Remember this was made by Sun, the people who brought you RPC.
[P] It is possible that Java.io.File et al could have avoided some
silliness by pathname translation -- in other words, '/' is always
the path delimiter, and there is only one root, so that G: would be
mapped to, say, /g.
Then you would need a) to have a to-from mapping layer and b) train
platform developers to write paths in a different manner than they're
used to.
What's needed is for Windows programmers to learn that they can use
forward slashes. And old MacOS is dead.
[M] The "webbrowser" of javax.swing.JEditorPane has many problems.
That's because (as I understand it) it was made simple (understanding
only HTML 2.0 and CSS 1.0) intentionally, so as not to ruin the market
for developers who wanted to make more heavyweight components (like
ICEBrowser). Of course, the component market largely died out as Swing
got a bad reputation (undeserved, as any user of Swing-based Borland
JBuilder can attest) and people for some reasoun started making web
applications instead.
[M] A PDF Swing viewer would be nice. There might actually
be one, but if so I'd have to find it; it's not part of
Java currently. RTF, strangely enough, is.
Adobe made a Java-based PDF viewer:
http://www.adobe.com/products/acrviewer/acrvdnld.html
[M] Built-in support for ASN.1 would be nice as well. Admittedly,
ASN.1 has apparently been relegated to "just for SNMP traps",
despite the fact that ASN.1 can in theory replace RMI entirely, much
like SOAP. Watch this space.
ASN.1 is one of those binary formats that grew out of ISO. It's lack
of popularity can perhaps be attributed to the lack of popularity for
other ISO things like X.400 (ISO MOTIS) mail.
[P] Is there a good reason why Runnable.run() can't throw a
Throwable? (Apart from the perhaps obvious one of trying to
disentangle Throwables in the calling thread, which are not thrown
by the calling thread?)
Well, it would end up in the ThreadGroup's uncaughtException() method,
but who here actually use ThreadGroups and that method for anything?
[P] ThreadLocals are interesting. Are there better methods by which
a Thread can have its own value of certain statics? For example, a
Thread might extend Comparable, allowing Threads to be put into the
key side of a Map. Of course the user could implement that himself,
but this is a little weird.
The problem is that Threads have a very specific purpose, and should
stick to their designated role, and not become general-purpose
objects. That's for the object implementing Runnable (that the Thread
manages) to do.
[?] Is java.lang.ThreadDeath going away anytime soon,
since the only method causing it is deprecated?
Deprecated items just rot and stink, they never go away. Backward
compatibility for the win!
