Summary of JDK1.5 Language Changes 839
An anonymous reader writes "Over at java.sun.com, there's an informative article about the new features in JDK1.5. Some of the changes like generics are nice and should make some things easier. Some of the enhancements to me are purely sugar, like enumerators. When it comes down to it, once the code is compiled, it's the same. The thing I hope is, some of this new syntactic sugar doesn't result in more obfuscated code. Unlike some people, I feel using programming shorthand leads to increased maintenance. This is especially true when you have to debug a complex application."
enumerators (Score:4, Insightful)
Re:enumerators (Score:4, Informative)
The type-safe enum pattern shows the correct way of handling enumerations. And you can the Jakarta Commons Lang library [apache.org] to make it a bit easier.
Re:enumerators (Score:4, Funny)
Re:enumerators (Score:5, Insightful)
The article makes no claim about the typesafe enum pattern being broken, it just points out that you have to be careful if you use it and implement Serialzable. This is something that Bloch specifically addresses in Effective Java, and does not mean that the entire pattern should be scrapped. You just have to be aware of potential problems.
Re:enumerators (Score:5, Interesting)
Evil thought: you could get relatively nice-looking static instances with methods if you combined enums with anonymous inner classes...
Re:enumerators (Score:4, Insightful)
I would think they'd have to be like singletons, with the compiler creating exactly one instance of each enum value.
Re:enumerators (Score:4, Informative)
public class Season {
static public final Season spring = new Season();
static public final Season summer = new Season();
static public final Season fall = new Season();
static public final Season winter = new Season();
private Season() { }
};
Except it's only one line, there are useful additional methods (like a toString), and you can use it in a switch statement.
Re:enumerators (Score:5, Interesting)
I don't use ints for my enumerations anymore after reading Josh Bloch's Effective Java. The type-safe enum pattern he recommends is fantastic.
For those not sure exactly how it works, you simply create a class to represent an instance of the enum, and you make the constructor private so that no one can create their own instances. Then you just provide a public static instance of the class for each enum.
I used this pattern simply to achieve its intended effect of providing an enumeration, and then later found that by adding methods to the class, I could even give behaviors to the enumeration instances! Try doing that with an int. This was far more elegant than creating a giant "if" statement and performing conditional logic to test the value of the enumeration, because I simply used a polymorphic method call.
An example:
You get the main idea. No, not as fast as an int, but far more powerful.
Re:enumerators (Score:5, Interesting)
It's nice to see Java stealing something from C# for once
Re:enumerators (Score:4, Interesting)
Re:enumerators (Score:4, Interesting)
You simply do not need to use switch when you have polymorphism, which is a much more powerful mechanism and allows for much nicer scalable, maintainable, and readable code. Of course, this assumes that one has an understanding of OO.
If there is a problem with safe enums, it is with serialization and deserialization. There are a number of solutions available for that, however. Personally, I feel that those should have gotten in the Java libraries, not enums in the language, but oh well.
available such as , something that the safe enum provides, unlike the enumerations.
Generics (Score:3, Interesting)
Re:Generics (Score:5, Interesting)
Re:Generics (Score:3, Insightful)
Re:Generics (Score:5, Informative)
http://developer.java.sun.com/developer/earlyAc
Re:Generics (Score:3, Insightful)
For some interesting words on generics, and implementation for both Java and M$ CLR take a peak at this link:
http://msdn.microsoft.com/library/default.asp?u r l=
All you "I hate M$" people out there will more than likely
Re:Generics (Score:3, Insightful)
No, they are not. In fact, they are very different. C++ templates are heterogenious (every parameter set means a new class, hence you get lots of additional classes); Java generics are homogenious (one class serves all parameters). C++ templates' requirements for the parameters are "as they come" -- the code is simply recompiled with the new parameter classes; Java generics' parameters need to implement interfaces/extend classes if a particular me
Re:Generics (Score:3, Interesting)
List<Foo> list = new ArrayList<Foo>();
list.add( myFoo );
Foo otherFoo = list.get( 0 );
The compiler will interpret the second and third lines as if they said:
list.add( (Foo)myFoo );
Foo otherFoo = (Foo)list.get( 0 );
It's a pretty elegant way to incorporate type-safe generics without imposing any changes on
Re:Generics (Score:3, Informative)
The method compareTo is supposed to override the method in Comparable, which takes an object. So they create a bridge method that overrides it normally:
Re:Generics (Score:3, Interesting)
The JVM executes a checkcast bytecode instruction wherever there is a cast. It either does nothing or it throws a ClassCastException at you. (The instanceof instruction works the same way, except it puts a boolean on the stack instead.) But with generics, a runtime cast is never required IIRC. The compiler generates a one-shot collection cl
Re:Generics (Score:3, Insightful)
By comparison, by telling the compiler that you want all of the objects in some container to be
Programming shortcuts (Score:5, Funny)
I agree. This is why I never create my own functions or methods. Evey program should be just one big function.
Re:Programming shortcuts (Score:5, Insightful)
Oh, do I agree, in boldface.
Re:Programming shortcuts (Score:5, Insightful)
The ultimate removal of "syntatic sugar" would take you down to raw machine code. I do not believe that would be easier to maintain than Java, or pretty much any higher level language. The aim of syntatic constructs is (or should be) to make it easier for the developer to express the algorithm clearly. It's not about saving typing (unless we're talking perl) and not about being smart for the sake of it, it's about making it easier to read and understand.
Re:Programming shortcuts (Score:4, Insightful)
Re:Programming shortcuts (Score:3, Funny)
Maybe it's just me, but I think operator overloading is closer to syntactic poison than syntactic sugar
Re:Programming shortcuts (Score:4, Interesting)
Enumerated types will save your ass the first time you change databases or some project manager adds a new "status level" in between DONE and FINISHED. They are much faster than using internalized strings, which is how I had been testing for this crap. Remember, once they hit the object code they're just constants anyway...
Foreach was easily the coolest thing about C# when I started using it, indexers were the second, and the code they create is FAR more maintainable than for(Object o = someList.FirstItem(); o != someList.LastItem(); o = someList.NextItem()){
Automagic "boxing" is a beautiful thing for newbie coders...I have had to teach so many the difference between a Byte and a byte that it isn't funny. I intend to use it, too...we pass in and out of the classes for char, int, byte, bool etc so often it makes sense to have the compiler/VM do our dirty work for us.
And generics...well, they look real queer in Java, where we've never used the syntax before. But they will save our behinds on reuse! Besides no doubt being faster, it will make more sense when typing collections of inherited objects. We have a BaseRecord class. We have an optimized BaseRecordColl class, usually full of different types of ChildRecord classes. If we can write the one collection class, and not have to explicitly cast each child op, it will save time, space, and hassle...and avoid calling the superclass methods of uncast subclasses!
Metadata is the only ingredient here that seems like it could cause trouble, and if it does it will be because people are using it wrong. Java is not a language that inlines...that's the whole idea of the JIT...and with today's cut and paste GUI IDEs, there's no need for programmers to use the lazy C declarations of the past. If people start doing so because it's neat, just nip it in the bud. Find/Replace when the code hits your desk. Eventually they'll get the hint.
Re:Programming shortcuts (Score:4, Interesting)
Every language has idioms, and a programmer should use those idioms in preference to other allowable ways to do things unless they have a good reason. It's all just part of good style.
Agreed.. (Score:5, Insightful)
Re:Agreed.. (Score:5, Interesting)
(Just goes to show there will be differences of opinion and no such thing as "the" right way. Here's another example:
if( x == 5 ) { do something }
versus
if( 5 == x ) { do something }
Some prefer the second way because it puts the term which cannot be a valid lvalue on the left side, thus if you make the common typo of "=" instead of "==", you will get a compile error from it, which wold not happen for x = 5. But, it looks very odd to write it 'backward' like that, so some say the readability of doing it the 'dangerous' way makes it worth doing it that way.
There is no such thing as "the" best way, not even in Java.
Re:Agreed.. (Score:5, Insightful)
Actually, i believe that in Java
if(x = 5)
will throw a compiler error because (x = 5) does not resolve to boolean.
That is something I like about Java, it doesn't allow you to do stupid things like that. There is no reason to do an asignment in an if() statement.
I disagree - x++ vs ++x (Score:4, Insightful)
As for your equality test examples, putting assignments in if statements in Java gives you a compile error. Also, it's quite rare to ever put a specific number in an if statement, and if you do it's likeley to be 0.
Yeah, but... (Score:5, Funny)
if( xxx ) versus if( xxx ) (Score:4, Insightful)
It is as if "if" is a function putting the parentheses like that.
foo( xxx ) is a function call
if ( xxx ) is a statement which gets a block in parentheses.
I couldn't resist. I have to fight this good fight every day against some of my colleages.
So basically C# minus generics (Score:3, Insightful)
Where are true properties though?
So C# is basically Ada without strong typing? (Score:3, Interesting)
Seriously, the "C# copied from Java/Java copied from C#" argument misses the point. There's a lot of prior work, and finding the right balance between usability and clutter is difficult. As much as I loved writing stuff like "for (value'range) do..." I would rather see a conservative approach to features since it's always easier to add stuff than remove it.
Longing for the good ol' days (Score:5, Funny)
Q: What's wrong with happy/contrived Q&A "articles"?
A: I was hoping you'd ask!
While humor and a semi-light tone are good ways to make technical discussions accessible to more people, treating folks like children who need to be entertained and talked-down to does more to alienate professional developers than it does to attract new converts.
Having said that, I am *really* looking forward to the "foreach" in 1.5 and the auto-boxing/un-boxing. While mucking with an established language is tricky - and potentially dangerous (from an acceptance p.o.v.) - the community process seems to be working out well for Sun and giving developers what they have wanted for years.
Let's just hope that the next "preview" of new features is more in the style of traditional FAQ's.
Wow, how intelligent (Score:5, Funny)
Hell, lets write everything on fucking Turing machines then.
Re:Wow, how intelligent (Score:4, Funny)
I love the language. It's the lack of libraries that kills you.
programming shorthand (Score:5, Funny)
My code was hard to write to it should be hard to read.
Re:programming shorthand (Score:3, Insightful)
Much, much more than syntactic sugar (Score:5, Insightful)
FYI: Generics are _much_ more than mere syntactic sugar (as are enumerators, a weak form of algebraic datatypes, if handled type-correctly).
These are actually the kinds of things that make program maintenance considerably easier, since they allow more concise specifications of intended semantics to be done. No longer having to typecast (and thus expect run-time exceptions) when using a "vector of FooObjects" gives more power to the type checker, and thus allows a much richer class of programming errors to be detected at compile-time. This is the one major improvement in Java that's been missing since its very inception.
But note that "generics" or "parametric types" have been present in languages such as Eiffel or Sather for well over a decade, and for much longer in ML. In a way, it's embarrassing that such an essential feature was added this late during development.
Uglification? (Score:5, Insightful)
It appears that Java's way to solve run time errors is to screw the bolts as tight a possible during compile time. Will generics become THE way, or just remain one of the options?
Re:Uglification? (Score:3, Insightful)
But for that other 10% of the time, remember that all classes are children of Object, so I'm betting you c
Re:Uglification? (Score:5, Insightful)
If your only experience of generics is C++, then all you've seen is the *worst* implementation of generics ever done in a language. Template code is almost unreadable. (Have you ever tried debugging one of the STL implementations?)
Besides, the lack of generic types cripples Java's ability to do static type checking, since your code ends up being full of things like this:
Foo f = (Foo) vector.elementAt(i);
where type errors can only be detected at runtime. That not only makes it impossible to detect errors at compile-time, it hurts performance at runtime.
Check out how generics are handled in Modula-3 for to see a much better way to handle them than C++ templates, or look at ML for something even more groovy (ML uses polymorphic type inference instead of generics, so you don't even have to mention types - the compiler just does the Right Thing).
Once you've worked with a good generic implementation, you'll never want to stop using them.
Harry
Re:Uglification? (Score:5, Informative)
Well, generics remind me of C++ templates
They're not quite the same; C++ templates are essentially glorified preprocessor macros with
some relatively small checking and a rather baroque
underlying functional language. Generics are more
concrete than that.
Not to mention that attached to variable name doesn't make code any more attractive to look at.
It would be really neat to have type inference there
It appears that Java's way to solve run time errors is to screw the bolts as tight a possible during compile time.
That's the idea, and that's also what I try to do when writing programs. Why should I have to write half a dozen test suites for some simple program property if the type checker can tell me whether it'll work right?
Remember: Compilers don't do type checking just to optimise, but also to catch programming errors. And Generics allow you to catch a much more interesting class of these.
-- Christoph
Retro... (Score:3, Interesting)
One line summary (Score:5, Funny)
compilers never make mistakes? (Score:5, Insightful)
Because the compiler, unlike the programmer, never makes mistakes, the resulting code is also more likely to be free of bugs.
That's right, none of us has ever seen bad code generation or an internal compiler error. But, he does have a point. The compiler is less likely to make a mistake than a programmer.
not just sugar (Score:4, Interesting)
To add a property, say a String called name you have to write:
* The name of this object.
*/
private String name;
* The name of this object.
*/
public String getName() {
return name;
}
* The name of this object.
*/
public void setName(String name) {
this.name = name;
}
That's 16 lines of code for one property! This is tedious to write, and more importantly, very hard to read when you have many properties.
This could easily be reduced to something like:
* The name of this object.
*/
property String name;
expanded to exactly the same code as above by the compiler. Incredibly useful if you're, say, writing a lot of value objects in a j2ee scenario.
Problems with less verbose accessors (Score:4, Insightful)
Note that you now don't have anyway to specify access and protection! I had given a little thought to better ways to handle this, and even had an interesting brief email exchange w/ a C# engineer about it. For the protection aspects you could do something like [this is just a quick idea I cam up with:]
property access String name;
where access is one of {read, write, readwrite}
But note taht right away you have a problem -- no way to assign protection levels to the various access, which is really a cross-product. What happens for example if you want the getter to be public, but the setter to be private?
Also, note that you would also need semantics to handle overriding the property accessors. You could just say that the property access defines an equivalent to the getter and setter methods, but that can get weird and confusing very quickly. Think about the situation where you have an interface defining getters and setters and then you implement it by just providing the one-line property definition. That would not be very transperent TSTL.
All this is just to say that it is a noble goal, but not as trivial as it sounds at first glance. IMO, the C# "solution" is particularly ugly, and qualifies strongly for the "syntactic sugar" label.
FInally, as in my other note, good IDEs like IntelliJ provide very convenient ways to auto-generate these things. I care much less about this issue now that I am not having to type all this stuff out by hand!
Re:not just sugar (Score:3, Informative)
You really need to try a generating/refactoring IDE like Eclipse [eclipse.org]. I once held to the orthodoxy that if I needed more than emacs then something was broken in the language. I grew up on object systems like CLOS where if you wanted a getter or setter you just asked for it in the definition of a field. So at first C++'s lack of public read-only/private read-write vars ann
Shorthand programming (Score:5, Funny)
#define FOREVER for(;;)
#define BEGIN {
#define END }
#define ONE 1
#define PUSHORT unsigned short *
#define DONE goto end
The first thing an amateur programmer does when assigned a new project in C/C++ is to go redefine the language and all the types. I scolded them for these kinds of things, knowing that once they were forced to read other people's code often that they would realize how stupid these kinds of things are. Unfortunately, once I started my career in embedded development, I quickly learned how stupid I must have been to think that people left these behaviors behind in college... (all the above examples are taken from "professional" code that I've seen in the last few weeks)
Re:Shorthand programming (Score:3, Insightful)
#define NOTHING
...
if ((flag & VAL1) || (flag & VAL2)
NOTHING;
else
I know I can change this to eliminate the empty
';', but I choose not to, because I feel that the conditional reads better as a positive statement.
[I also prefer to have the '<' or '>' in a compound conditional always point the same way:
(5 <= x) && (x <= 1
Re:Shorthand programming (Score:3, Interesting)
Interestingly, ISO C defines shorthands for people with crap keyboards. You can type <% instead of { and %> instead of }. Also:
:> means ]
<: means [
%: means #
%:%: means ##
You get even more if you include iso646.h. Of course, the old compiler you were using may not have had thes
Re:Shorthand programming (Score:3, Insightful)
I know I can change this to eliminate the empty ';', but I choose not to, because I feel that the conditional reads better as a positive statement.
At the cost of failing to compile
Some quality stuff - competition is good! (Score:5, Insightful)
Some of this other stuff has been going on for ages - I'm curious about the metadata/declarative programming features. I've developed complete code generation systems for Java - the number of situations that require reams of very repetitive code in your average large-scale Java app is huge, and much of that can be automated. It would be great to see a consistent, standard system for doing this built in as a language feature rather than having hundreds of home-rolled systems everywhere, but the nature of many problems lends themselves to home-rolling. I can't tell you how many times I've written simple SAX parsers that spew out Java code, and rolled up an ant target to run it on some schema and package up the result. It's not clear from this brief example whether this is only for XML/RPC or whether there's an extensible metadata system that you can build on top of.
Then again, we should be careful not to roll too much into the language itself. I think generics, autoboxing, and enumerators are fabulous. Iterators I could give less of a shit over. Other stuff is great, but I question whether extending the language is the right mechanism. Much of the power and flexibility of Java comes from its simplicity. And most importantly, the ease of reading other people's code - there's far less stylistic variation because there are only N ways to do a task, rather than N! ways to do it, like in C++ (don't get me wrong, for a lot of tasks, I'd never dream of doing them in Java, like 3D programming). But it takes me about 1/4 to 1/3 the time to assimilate and learn a new Java API or library as it does to learn your average C++ API or library, and that's the appeal of Java.
Of course, I'll be thanking the gods that I never have to deal with the fugliness of casting and wrapping to move stuff between typed arrays and untyped Lists again.
Enumeration classes (Score:3, Informative)
final class Color {
String c;
private Color (String color) { c = color; }
String toString() { return c; }
static final Color RED = new Color("red");
static final Color BLUE = new Color("blue");
static final Color GREEN = new Color("green");
}
You can then treat this class like a type-safe enumeration. It doesn't have all of the nifty features that you'll see in languages like Ada, but it has the nice property of allowing you to attach whatever information you want to the enumeration class.
You can also use this approach to create self-initializing classes, e.g., a list of states (including full name, postal abbreviations, shipping zone, etc.) from a database. You can access the enumerated values through a collection class, a "lookup" method, or even reflection.
Uh, read the article (Score:4, Informative)
Article didn't mention new concurrency stuff (Score:5, Interesting)
Bascially, the goal of JSR 166 is to do for concurrency programming what JDK 1.2 did for data structurs (Collections stuff). The gist is, you'll never need to use "new Thread()" or "synchronized" anymore, but rather you'll execute Runnables, use Locks and Semaphores, etc. Also, queues are *completely* reworked to be ultra scalable.
JSR 166 is based on Doug's concurrency package:
http://gee.cs.oswego.edu/dl/classes/EDU
OH, and there will be classes like AtomicLong which guarantee atomic 'compare and set' options for primitives.
Cheers!
Re:Article didn't mention new concurrency stuff (Score:3, Funny)
Sounds like a "super" class to me.
Re:Article didn't mention new concurrency stuff (Score:3, Funny)
Sounds like a "super" class to me.
Sounds like a porn star's name to me.
JCP strikes again (Score:5, Informative)
"synchronized" vs. locks & semaphores (Score:3, Interesting)
I'm not sure how locks and semaphores are a step forward from monitors, which is what "synchronized" represents.
Are you claiming "synchronized" is inefficient? Did you see the developerWorks article [ibm.com]?
Are you claiming that such a high-level structure as a monitor is unnecesary for real programmers, who know what they're doing and will never screw up using synchronization
Re:Article didn't mention new concurrency stuff (Score:4, Informative)
How this compares to C++ (Score:5, Informative)
The new Java generics are really weak compared to C++ template support. This is probably partially due to difficult in compiler support and also complexity (templates are without a doubt the most complex feature of C++). I was disappointed though in Java generics mainly due to lack of any kind of specialization support and also about the strange paradigm used for Iterators (instead of an iterator being class defined with a consistant interface, it's an external class that just behaves that must wrap a behavior around the class).
Enhanced for loop
This is for_each() in C++. Now, with for_each, you have to use function objects which is arguable as to whether it's more readable. Fortunately, Boost has developed a boost::lambda class that allows for code to be used as the third parameter. This is _really_ neat.
Autoboxing/unboxing
I presume this means that primatives can't be used in generics.. That's kind of sad. This isn't a problem in C++.
Typesafe enums
This would be a nice linguistic pattern to have in C++. As it stands, the equivalent would be:
struct Coin { enum { penny, nickel, dime, quarter }; };
Static import
This can be achieved via using in C++. Of course, Java doesn't even really have a namespace paradigm so it's not really a fair comparision.
Metadata
This is.. well.. strange. I didn't see the syntax for doing something like this. If it is just keyword/code replacing, then an #include directive would work just as well.
Re:How this compares to C++ (Score:5, Informative)
Metadata
This is.. well.. strange. I didn't see the syntax for doing something like this. If it is just keyword/code replacing, then an #include directive would work just as well.
IMO, metadata is the coolest thing. It's a feature of C# which has had little recognition despite its coolness.
In both Java and C# you can use reflection to find out information about a class (class name, method names, etc). Attributes/metadata allow you to attach information to just about every element of a class/struct so that it can be queried dynamically using the reflection apis.
Imagine them as JavaDoc tags that aren't discarded at compile time but are instead compiled into a class's meta data. They'll do for source code what XML did for HTML -- give more meaning to the code.
Here's an example of using attributes/metadata to simplify XML serialization:The C# XmlSerializer class dynamically generates the IL that will do the serialization so it is *very fast*. It knows how to map the field names to element/attribute names by inspecting the attributes.
Some other obvious uses include object/relational mapping (no need for external XML mapping files) and XMLRPC (just mark a method as Remotable!) etc. You can imagine infinite other uses for attributes/metadata.
I'm not sure how it works in Java but in C#, attributes are simply classes (usually with a name ending in 'Attribute'). You can define your own custom attributes and your own classes that work with them. It's very cool.
Re:How this compares to C++ (Score:3, Informative)
struct Coin { enum { penny, nickel, dime, quarter }; };
Not equivalent, the Java version also supports writing as a String
System.out.println("coin: " + Coin.PENNY);
What Bjarne Stroustrup has to say about Java (Score:5, Informative)
This is what he said about Java [att.com] and the [att.com] likes [att.com].
Also here [eptacom.net].
When will Java be 'frozen'? (Score:3, Interesting)
One of things that makes older more mature languages like Common Lisp (and perhaps Smalltalk) nice to work with is a feeling of both having really solid implementations and not breaking legacy code.
I like the idea of boxing and generics, but, these changes will affect old code (probably?) and the platform in general.
My vote would be to freeze the Java language (perhaps after 1.5) and concentrate on the following:
I would not like to see Java become a language designer's playground.
Because of great infrastructure software like servelt/JSP containers, (perhaps EJBs :-), XML utilities, solid web services support, etc. Java is a great platform.
Leave it alone (the sooner the better) except for improvements in the implementation.
-Mark
Re:When will Java be 'frozen'? (Score:5, Insightful)
* memory footprint
* runtime efficiency
Leave it alone (the sooner the better) except for improvements in the implementation.
This is a good idea. However, my vote is to concentrate on Java3. Screw backwards compatibility going forward and fix the standard library. Throw out the crap that has come along from JDK 1.0-1.1 and make the platform consistent. Why do we have both Enumerations and Iterators? Why are constants mostly UPPERCASE but sometimes lowercase (see java.awt.Color)? What about Thread.stop()?
This cruft is never going to go away until Sun releases a version of Java that isn't backwards compatible. Perl and Python do it. Java should too. It makes for a much cleaner language for new projects. Old projects may get stuck on a Java2 platform until the owners invest the time to convert them, but that's the way things go. It's time to clean out the cobwebs in Java and make better use of the new features.
Once all the old crap is gone, then it will be time to freeze the language and standard library.
This is a sad day for me. (Score:3, Interesting)
To the many cooks who spoiled the broth: "Thanks a lot, assholes."
I think these are all great... (Score:4, Insightful)
for (TimerTask task : c)
task.cancel();
becomes
foreach (TimerTask task in c)
task.cancel();
Re:I think these are all great... (Score:4, Informative)
Re:I think these are all great... (Score:3, Funny)
Programming Myth (Score:3)
False.
Shorter code and more powerful idioms makes a program *easier* to debug.
Too much code makes the purpose lost in the noise. Consider:
foreach (@array) {foo $_};
and
my $i;
for ($i = 0; $i < $#array; $i++)
{
foo $array[$i];
}
(I use Perl here since it is well known and I can show the 2 idioms, but really Perl isn't the clearest language of all). One form is much clearer and reveal much more eloquently what is the intent of the code.
Of course, this doesn't mean that shorter code "at all cost" is easier to debug, it means that "less code" is better.
Oh, and also it pisses me off when management tells me I need to use only certains idioms in case someone comes over my code and don't understand it. I hate to have to program like the next maintainer will be clueless and ignorant.
Automatic boxing/unboxing (Score:3, Interesting)
Actually, I think that's a bad idea, since you wouldn't be able to tell a zero you put in a collection with one that you didn't. Personally I'd like to see this as an option, somewhere. perhaps as a parameter to Integer, so you could do Integer<0> or Integer<null> to chose the behavior of the class. The problem there is that it's not obvious what a parameter to integer would do. Although I suppose you could use an if statement.
Personally, I wished they would have thought up a more interesting way to do generics then the C++ model. I wonder if this is going to give us the full range and power of C++ templates in java.
Just from pesonal experience.. (Score:5, Insightful)
Each and every point on this list of additions to the languages addresses problems that I have personally run into in my use of Java at work. These things will make the writing and maintenance of java projects small and large much, much easier.
Generics: Thank you God, yes! Having to explicitly cast objects out of Containers is tedious and error-prone.
Iterators/Enhanced 'for': Make iteration much easier to read and understand.
Autoboxing/Unboxing: This helps alleviate the enormous kludge that is the Object/primitive dichotomy. Casting to and from wrapper types just to pass ints, etc. around really sucks.
static import: Not having to fully specify tedious class names to access static members is a big boon for making stuff digestible and easy to read.
Metadata: Writing boilerplate sucks the big one. How many hours have I lost writing boilerplate? Way too many. Having language support for generating code from the metadata cuts my implementation times way down.
I could sit here and argue with folks about the 'new Java' versus C++ or C# or Smalltalk or whatever endlessly. But man, these things sure make Java a whole lot more pleasant to use.
What about making the language useful (Score:5, Insightful)
The memory foot print for loading Java is 20meg + and growing. I am part of a team that has been developing a complex Java application for the last few years and we have created about a 3meg library (and it probably does at least as much as the more popularily used Java classes). I have looked at some of the source code for the core Java libraries and it is clear that a good rewrite could reduce this footprint by a factor of 2 to 4. Currently, C# loads with a footprint of 2 meg to 4 meg. Most other scripting languages usually have engines that are about the same size. To put it simply, the base core Java libaries are unjustifiably large. Maybe if Java were truly open source this could be addressed, but of course Sun doesn't even believe in submitting Java to a standards board.
You cannot load the Java VM once and run multiple processes (note "processes", not "threads") from the same Java VM memory footprint. I hear that such a thing is becoming possible for C# on Linux. You would have to build all the core Java classes into a "DLL" or ("so" on Linux), but that shouldn't be so difficult.
You still cannot do basic OS operations in Java without writing your own JNI library. The one that stands out is the inability to get the ID for the current running process. The "nio" package has corrected some of these issues, but the "nio" package should be the "io" package instead of having two separate packages (similar to AWT vs. Swing).
Window focus handling is still terrible. Ever have two frame windows up, have a modal dialog pop up on one frame while you were looking at the other? The frame window without the popop modal dialog becomes unresponsive and the other frame cannot be reached by tabbing through the windows. Only if you are lucky and that window is still visible on your desktop can you successfully reach it. Also, if a user clicks on a button that generates a modal dialog, the frame is only locked out from user input once the dialog manifests. This creates the infamous "double" clicking problem.
Java's package management is still primitive. If you want to do anything more subtle then using the classpath to load in custom libraries, you have to write your own class loader. Having an auxillary file specifying parameterizable rules for class loading would be nice. It would also be nice if you could ask a running Java process what packages it had loaded (and metadata about them such as location and version). Compare this to C# (or the way some of the web server oriented scripting languages work).
Some of the basic core library functions have some major weaknesses. For example, the Hashtable should be written as a native object when using String lookup keys and also allow you to dictate the algorithm for creating hashes (ex: use first 8 characters, last 8, or middle 8). There should also be a non thread safe version as well as a thread safe version. The lack of such a natively implemented primitive object is one of the big reasons why some less cleverly implemented scripting languages (such as python) can beat Java in performance on many web applications. In general, the core collection classes should be implemented in pure optimized (down to the actual chosen assembly code) native code.
Many of the utility libraries are broken in fundamental ways. Send back a badly formed response to the HTTP library and you go into an infinite loop when it falls into its keep-alive/retry logic. Date parsing is still behind what is available in the C standard library. Locale specifications do not allow you to independently specify date formats, language, floating point format, currency format, and time zone. You get o
Re:Looking to Get Back into Java (Score:5, Informative)
http://www.eclipse.org/
Re:Looking to Get Back into Java (Score:4, Informative)
My roommate told me about it, and once I started using it I never looked back.
Re:Looking to Get Back into Java (Score:4, Informative)
http://www.intellij.com/idea/
Re:Looking to Get Back into Java (Score:4, Informative)
http://www.xemacs.org ;-)
what more do you need?
If you want a *real* IDE, I'd check out IntelliJ's Idea [intellij.com] product. It's a few hundred $$$. Lots of folks like Netbeans [netbeans.org] and IBM's Eclipse as well (sorry, no url to eclipse, but I'm sure you can find it). The latter 2 are opensource.
Netbeans (Score:3, Informative)
Re:Looking to Get Back into Java (Score:3, Funny)
Harsh.
Very cruel man.
Re:Write once, Rewrite forever? (Score:5, Informative)
Re:Write once, Rewrite forever? (Score:3, Informative)
Re:Write once, Rewrite forever? (Score:3, Insightful)
What part of the new syntax would cause old code to break?
Re:Write once, Rewrite forever? (Score:3, Insightful)
List words = new ArrayList();
You'll have to say:
List<String> words = new ArrayList<String>();"
The way he says "you'll have to" suggests that old collection class construction might break. Let's hope that something like new ArrayList<Object> becomes the implicit default if you don't otherwise specify a type.
Re:Write once, Rewrite forever? (Score:3, Interesting)
Huh? Where did you see that?
It looks like they're making changes so that new apps won't compile on older compilers, not that old apps won't compile on newer compilers.
They risked a backwards compatibility problem when they introduced that "assert" keyword in 1.4 but there is a compiler switch to turn it off if you have variables with that name. Before that, they haven't messed with the syntax s
Re:Give billg his due... (Score:5, Insightful)
It's more that C# includes a bunch of features that some java programmers had been asking for, and so does java 1.5. It's not like any of these features were out the blue in C#, they are mostly things people have been missing from other languages.
Re:Give billg his due... (Score:3, Insightful)
Actual example, I recently developed a servlet-based application, and given the hardware and time constraints I was under I developed on Linux, performed functional testing while deployed on Windows, and finally deployed on Irix. There was no change in behavior with the application other than p
Re:Everything must change... (Score:3, Insightful)
Now, if you want a weakly/dynamically/non-typed language, you should use one, and deal with the inevitable tradeoffs. It's not like there's a shortage of non-strongly-typed languages out there.
Re:Why I don't like Java (Score:5, Interesting)
Typecasting is a tool -- do you really trust the compiler to recognize exactly what you mean in every scenario, throughout your hundereds of thousands of lines of code? I don't want to have the compiler (or run-time environment, or interpreter, whatever) to "guess" at what I mean -- I want to tell it exactly what I mean.
<flame> Perhaps this is why huge applications are usually written in languages requiring typecasting, and the "looser" languages are usually relegated to simple task duty.</flame>
Re:what if... (Score:3, Insightful)
What happens when matter meets anti-matter?
1) Microsoft wouldn't have a clue how to manage Sun. Sun is a hardware-engineering firm with a different corporate culture than Microsoft.
2) Most of Sun's employees would either quit or sight tight until they can quit.
3) Sun's customers would leave for IBM or HP; they would not eat MS' dog food.
4) The Justice Dept. would actually do something for once, because J2EE is the only big competitor to
Re:Where is operator overloading? (Score:3, Interesting)
Re:Where is operator overloading? (Score:3, Informative)
There was a preprocessor named jpp floating around a few years ago that supported operator overloading for Java. It seems to have vanished off the net in the meantime, though I'm sure I have a copy somewhere. True operator overloading is supposed to be added to Java at some point
Re:Hope it fixes issues with 1.4.x (Score:4, Insightful)
memory leaks (StringBuffer ToString anyone?).
Sorry, not a bug. What happened is the JDOM folks (gambling) relied on the internal implementation of StringBuffer and not its public API. That also broke JDOM for 1.2 jvms, which implemented StringBuffer differently. The internal implementation changed in 1.4.1, hosing the JDOM folks. Sun's only mistake was making this change in a minor version instead of a major one.
Re:ooooh baby (Score:5, Funny)
You don't get out much, do you?
Re:foreach (Score:3, Insightful)