WWDC2000 Session 184

Transcript

Kind: captions Language: en my name is Blaine Garth I'm the manager of one of the Java groups at apple and what we're going to talk about today is Java in depth so I want to just jump into it I'm actually going to try to have some fun today so hopefully you'll have some fun with me we're going to try to do a little bit a few demos and show you what's really going on inside Mac was 10 inside the Java Runtime environment and stuff so the demo God's struck early so at eight o'clock this morning the system wouldn't boot off of our boot disk so we got that figured out at eight-thirty and at ten minutes to eight we figured out that our login user names weren't quite the same as what they were the last time we ran the demo so you know they're striking early but I think by the time we get to that point we'll have things pretty much in control so so far at this conference you heard from Stephan are off about the overview of what we're doing where we've been where we are now and some of what we're trying to go where we're trying to go you may have slipped over and listen to the QuickTime talk after that found out how to do really cool graphics programming Annapolis 10 much as you do 19 you may have gone to Pete Dye hours talk on how to cook up a job application I'm not going to try to repeat very much of those previous slides nor the performance talk either but what I do want to talk about is some of the stuff that's that it did get talked about so this is the talk where you get to ask questions where we're going to try to give you detail more detail more you know type that when project filter doesn't quite do what it's supposed to be doing for you quite yet some of the tricks we use or some of the things we have to use in the interim until it does so it's nine o'clock have you had your Java yet pop quiz what do the following screen shots all have in common set of assistant the first program that runs after you to act was ten network manager when you find yourself in a strange and unworldly NFS environment this is program you run to untangle yourself blast app source code and a game that chips on your ships on your CD a an applet perhaps the you're kind of getting the idea here jbuilder you saw that running yesterday it unfortunately is not shipping on your CD and you're supposed to go talk to Blake if if you would like to see it shipping on your CD sometime quicktime digital media is i mentioned before and of course the answer is they're all written in java now this isn't supposed to be all that remarkable is it but i think it's really kind of neat java I mean these applications are kind of like when you walked up to Mac os10 they're like the walls of apps I mean you know you got a TV room you've got a kitchen you've got your living room and stuff I mean when you're inside the house and Mac was ten running these applications you don't really think about how they run or you're not really supposed to but for the folks of you inside this room when the wiring is what is important to you that is while you're here so what we're going to talk about is what's inside the walls of that house you know the Java wiring in detail so as a brief overview we're going to talk about the wiring in certain groove depth we're going to talk about once you get your your app up and running and more or less working you know how to run a little bit of profiling stuff against it where we'd like to go with that where we think we'll be going with that how to do some debugging right now both for your benefit and possibly four hours and there's a few things that you due to augment your applications and so we're going to try to go through a little bit more detail on how to do that in other words how to use Jay and I and our kind of an environment how you have to do today versus how we'd like to see you do it and a few other topics so let's just get going when you write your job application what you think about are the classes you right and of course when the program is running you know the data it takes up you know you can't just you know Alec you know go and read data forever because eventually despite what we do in terms of memory reclamation things like that if you're just leaking memory by holding on to it forever you know it's not going to work so the rest of the system however is a little bit more complex so what's under those covers is the stuff that we generally worry about at apple and we try to make the bottom part of this diagram you know as efficient as possible so I just like to talk so so let me go through the diagram first so of course you've got you know the JDK class is all I can't remember how many thousands of them there are that you might be using you know the runtime which does all that synchronization and garbage collection and compilation the compiler below that on the side what I have in green are jni support libraries both the ones that we use to keep things going and I just put two up there we have about nine and the Jan I libraries that you might be writing as well because you're bringing across and legacy code and stuff like that below if all or the frameworks that are common to macula step things like carbon things like the colonel things like you know all that other stuff that's below us that we all are clients of now private data is a little thin there it's actually private data extends all the way down at the side of that diagram in truth I would just want to put up the sort of the Java private data in this in this diagram but let's talk about the job of the M first of all if you were at peets talk yesterday you saw that the Java VM framework is sort of the fuse panel or Java inside necklace 10 we have inside that framework lots and lots of stuff we have the virtual machines that execute your java bytecodes we have all of our system jars in the classes folder things like that we have jan i support libraries wedged into some other little subdirectory we have headers because this is a sea environment for those of you writing jni code we have few headers for that actually probably on DP for a few more headers than we really need to have out there so the ones you should be thinking about her pretty much just jni we have the Java home with the system property file and you know there's a whole bunch of stuff and I'll let you wander around and take a look at that but that is you know sort of the moral equivalent to your NMR Jay programmer the the mr j libraries folder so in DP for i'll tell you the truth I'm really happy you guys have hot spot well he brought hot spot in just a few weeks before we should be before we've been working with hot spot for the year and a half we had some demos running last year at this time but keeping track tracking what they're doing shifting to their c1 compiler writing a compiler for the PowerPC takes a certain amount of time and so what you find on your GP for CD is actually the same environment that we shipped in DP three as well the classic interpreter plus the semantic jit compiler so we engineered this such that we could make a very easy switch over and so there might be some times when that's going to be of some advantage or some use to you to do that in different ways so the way we parameterize that is we have a symbolic link now we all know this is dump shock now you know this is a UNIX system underneath so symbolic links have some limited purposes and this is one of the ones we use it for everything that links against the Java Runtime links against this thing that's called lib JVM so we do some trickery such that that's all that any program that needs to be Jay and I ever sees when it does a link that way if it overcomes the path that you need to switch your Java VM you can reset that one symbolic point which the Macintosh terms is you know an alias really on on hfss file systems to be the vm of your choice so we ship in some ways three vm we ship hotspot client compiler as the default vm we also have a debug version of that same technology and i'll tell you a little bit about that later and again classic interpreter so there are several ways to get at that i really hope that you'd never have to reset that symbolic link honestly because we do it lots of ways to get to it here are two of them one is you can simply type dash classic or dash hotspot in order to have the you know the jni invitation code pick the right library to go after load up and initialize lift if you can't get to it via the command line or that inconvenient for you you can use a environment variable the J via or Java jbm library environment variable is also looked at and in that last line this is the preferred way to get to the say the debug version of hotspot now I want to caution you the debug version of hotspot is slower because it has thousands of assertions compiled in and so lots of C++ inlining that makes things really fast is an inline and so it's considerably slower but you're not really care about that if you're at stage and i'll tell you when you might get to that stage so here's here's a little bit about here's a little bit about profiling the hot spot or the JDK 12 the the java to specification for the runtime has a very nice interface it's called the Java Virtual Machine profiling interface and the implementation of that for the classic interpreter works pretty well but the implementation for that in the hot spot interpreter does not quite run there in your GP for we are working really hard with our folks and developer technical support to figure out a pathway to get you some updates to what's on your CD I mean you're what you see what's the bits that are on your CD or about two weeks old so that's a lifetime for us so what we have running up on stage and what you see on your in your CDs is slightly different it's our goal to try to get you what we have on stage including some project builder stuff out to you via the web very soon so in the interim however the hot spot itself is just chock full of very interesting technology so one of the things that makes hot spot really good is that it chooses which methods need be compiled on the fly and based on their usage patterns which in methods and the inline and ottoman line inside of there in order to do that it has its own sampling technology to figure out hey what's going on so every now and then clock ticks why's it goes and takes it looks at the stacks and figures out which methods are being interpreted and so an interesting side effect of that is that they've enabled that and sort of the profiling kind of a a manner such that you can get to that using the dash X cross flag so we actually have used that recently in the past two weeks we've used that to improve the launch time of a duty based applications by two or three seconds so what I'd like to do now is actually show you a little bit of demo of that and i'm going to have yen's al q join me on stage now the end as a few demos cooked up for us but if we could get there we go good to do way this demo is going to be in a terminal but not supposed to do that but if you really the only way to show off x cross right now so i have a command line all set up here what I've done is I've seeded into the directory of one of the silly little sample applets that you all know and love this one of Arc test and I'm going to run Java command I'm paranoid visited a demo so I'm going to force it to use hotspot and I'm using the magic dash X cross flag and then the regular Java arguments in this case just arc test an American named Klaus so what's going to happen is that it's going to launch our test normally but every time it's bread finishes it's going to spit out to the console some profiling data about that thread so as we launch our test which is going to come up in the background you'll first see the main thread finish and it's dumped out some stuff there here's our test do a little bit of stuff with it we quit our test and then all the other threads finish and we see their profiling information get dumped out too so what is this stuff it's really pretty easy to interpret it compared to the profiling out from JDK 11 it's not quite as in depth but it's fairly easy to read so first we've got the thread name here mane and first it's going to show us the profiling data for the stuff that got interpreted as opposed to the methods that we're running native says that the thread took four point one three seconds 240 for ticks and this confused me at first these are not text as in mac OS tix which were sixtieth of a second tick here just means samples so it depends on how many times it sampled it and so we spent eighteen point three percent of the time that this thread would active in j direct library OS X dot fine symbol which is part of the implementation of j direct three which actually is what goes out and maps the native methods to the actual carbon or system or whatever functions that back them up and the numbers here mean that we spent zero seconds and slided interpreted Java code zero ticks we're inside of interpreted Java code 26 ticks were inside of native code which makes sense we spent a whole bunch of time loading carbon basically is what this means and J direct looking at carbon methods and doing some GN I've stuff under the hood to plug them up then we spend eleven point three percent of our time down in view set geometry which is part of the core clipping code for heavyweight components and again that with all spent down in native code down below here the next group here is for the same thread but this is compiled code so this is time spent in actual methods that have been jitter to compiled into native code by hotspot and you can see there's almost nothing here the main thread just doesn't run very long it doesn't look that much it's mostly doing initialization stuff since that's the thread where the Apple actually creates the component and initializes the toolkit and all that stuff so these are a bunch of little threads that aren't doing very much stuff awt event queue 0 you'll find generally where most of the real work is happening in any java application that's the event dispatch thread here we spent twenty percent of our time down in CGS graphics AWT to corpse draw a line and so this is where we actually call into corpse to draw lines and so you'd expect ya in your civil kind of a WTF applets where you're going to be spending a lot of your time so if I said this is pretty straightforward stuff it's not going to give you the entire stack crawl of how you got to this method where you were spending all your time where the old profiler did and it does have to be run from the terminal but both of those limitations are being worked on and I think by the time we ship things will be better like GM get the other side back up ok so the traditional profiling stuff inside the job vm h bra we actually haven't run recently so on classic we believe it works so we strongly advise you to join that mailing list Makka lift and Java that our DTS folks run allen samuels will get up and tell you where that's at again and join us and help tell us what's what's there and what's useful to you and share some tips on that so we strongly believe that the jvm p I is going to be a super interface that third parties some of whom may be sitting in this room right now we're going to be able to take advantage of right away we have talked with some folks about this already and it's our strong hope that we get some rather awesome tools coming onto our platform and the profiling interface lets you want it fully operational tells you all kinds of things about object allocation stacks that were in existence when object camel came along so it's a very very powerful interface and we think that this is going to bring development on 10 a leap forward compared to some of the key based environments where these tools are or harder harder to accomplish so just as in wearing up a house or wiring up a circuit board or something you have debugging to do so again what you have in TP for is a classic interpreter that we've been shipping for a long time it has a debater interface it works and with hot spot we have one that almost works but it doesn't quite and so our folks last week working hard on getting the debugger interface up and running unfortunately we didn't quite get it where we needed to be for this demo today so I can't quite show you jbm di running on hot spot today but you can expect that that will be there very shortly and again we're going to try to figure out how to get updates to you so that you can see that as well so what's on your disk is a debugger interface it works in the classic environment so again you have to go to the command line to get use of that you have to go to jdv to see that so you should be using jdb dashti classic to fire up the runtime and get to set breakpoints and that kind of stuff obviously we don't think this is the way you really ought to be doing bugging and so we've been working with folks on the project builder team to make this a much more pleasant environment and we do have some success stories with that and I think engines going to share one of those with you a little bit later so the truth is you're going to have to find out if you need to do JTB level debugging you're going to have to find out how to launch this thing from the command line at the moment so if you happen to write those jni libraries then you're writing the key and so it might happen that you don't write perfectly the first time it might happen that you'll be interested in running GV on that part of your program that's written in C that gets called into across the jni interface in which case you need to learn how to launch jdb or GDP on the real job binary so the real job of binary is kind of wedged off in that little moral equivalent of mr g libraries its wedged in the java vm framework and so mentally concatenate the first two lines of this slide the font on the system or for the slides was an all so you essentially have to GD be the true java you know bring up executable in order to get attached to the current to that process there are a few things that you can do if you run with classic you don't have to run question but if you run with classic the next to line the call dump thread and the call gut monitors work and these are to some degree the equivalents to some of the mr JD commands that let you inside the runtime and see what's going on and a little bit more detail the last line is simply gbb syntax for doing a back trace on all the threads so that'll give you some idea of what's going on which ones have some of your code in the middle of it so I'm a little bit I'm optimistic that I'm also a realist so given that the hot spot that we have oh now we're going to skip the debugging demo right now redevelop it later given that the hot spot you have is actually fairly young it's very mature technology and it runs everything we can throw at it except that it's not fully functional but it's very solid but there might be some occasions where you'll trip across something that doesn't quite work right so one thing you can do for us is help you know and for yourselves that is determine whether or not some strange crash you see is your fault or ours so if your Java fed crashes one thing that you could do right away is just try running it in classes since it's a whole different technology underneath and it may well work there that's not proof positive that it's our fault but it's a good signal that it might be so if your code runs in classic but doesn't with the default hotspot you can do us a favor by running it with that debug version of hotspot because again there's lots of assertions in there and if there's something funky going on which might actually be your fault if you're passing in say a zero for a j-type environment pointer the debug version of hotspots going to catch that and throw an assertion whereas the compiled version of that long or might not so there are some cases where it'll it might text some things that are your fault and it certainly will catch things earlier if they are our fault and so obviously if you find something that is our fault we want to know about it and so I'm putting my email address up there right now for that you can mail me the details of that and I'll see that we get some attention page of that clearly if you're on our discussion with necklace 10 Java discussion list folks out there might well want to know a little bit about it also so again this is how you set up the hotspot debug there is an underbar between hotspot and debug it's hardly visible on this monitor but anyway so don't forget those under bars they are important ok so again this is a unix environment how many how many of you out there are have been exclusively mrj programmers okay there's just a few hands and so let me try ask a different question how many of you have already programmed in sort of the unix or windows environment the vast majority so you all know what this is going to be about okay so how do you build you know Jay and I support library you write some Java code with NATO's you compile it with Java see you build the sea header as necessary you can copy of the sea header / is your template and start hacking in your C code you build the library about the only thing that's different about this I'm a close Ted is that the the ending library there are two different types of libraries on Mac os10 one's called a bundle and the others called sort of several friends lovers there are two types of dynamic library one called the bundle and the other is called a dynamic library so we happen to like the bundle variant of the libraries for our purposes and so from a command-line viewpoint this is a very simple way to build one of those guys who just remember the dash bundle magic but I mean this is this is kind of messy and what we really want to do is put all the stuff inside a project builder and so one of our friends on the project builder team debuting has been stand until midnight his time which is Denver time trying to make this stuff happen so I'd like to bring ends back up on stage to see what some of this might look like inside project builder for it belong we get the monitor keep putting on both screens this time whether that's easy or not I'm bringing up a pdx project showing a very simple jni example that a plane worth the jni example and then debuting made the pdx project so I'm just here to be Vanna White and show it off we have a couple of files here we have calc engine dot C which is our native code just can't end a couple of jni methods I'm not going to go into too much detail there's not time the talks really explained jni and I'm numbers you've probably used it and there's some very good books up there in a Java soft tutorial calc Engine Java then the side you probably can't read the text on here anyway unless you're in the front row so we have a couple of native methods in here which are going to get bound into that native code what's interesting in here and this is just you know the tantalizing promise because you can't actually do this in DP for you're getting used to that line is we have three targets here we have the Java target which has calc Engine Java source file and we have a shell script here that's been cleverly set up so we're going to run the nfh and we're going to run this script that calls user din java h run that on calc engine so that's the post processing step so after we compile the job we were on Java H on it which then generates the header file declaring what native what the native jni functions are then we have a second target here for our jni library itself which is a regular kind of c target containing the calc engine via source file the cal attention dot H file that got generated by the Java target and this one the product type here is a library which is going to build a regular OS 10 bundl dynamic library then we have a third target and if you're used to codewarrior this will be second nature we have a third target Hulk Alec example which is just an aggregate target and the the other targets appear down in here which means that they are linked to it they're dependent on it it's dependent on them so building the calc example target will then build first the Java target and then the jni target and caused everything to be generated and as blaine alluded to earlier the demo gods were not happy we sacrificed beefy giblets to them but they really want to be tuna eggs and became very angry so we can't actually build this stuff it's actually more like file permission issues but I would have shown it running but you can just kind of imagine that yes it's going to kind of run and do it stuff we will ship this demo project went in this fabled upcoming release where we have a PBX support for doing the DNI stuff and that's it hmm did I say pdx ok so I think one thing in there that you probably may be noticed was that we had like four methods that were wrapped like add subtract divide multiply and I mean that's what those are the names of C functions and those were in fact the names of the you know native methods that we're going to give you access to that so if you've been on mr j before you know that that kind of a mapping is like kind of tedious in some ways so there is in mr j a better way to do that and that has been called j direct and so we have j direct three on necklace ten that both helps us out and can help you out with that so J direct three is pretty much the same as datarow too from your perspective not entirely the same but pre dog on the same and that's due to the heroic efforts of nick clegg zyk put together a j directory package which is pretty much entirely rewritten underneath but from your perspective it's not going to be that much different but there i will go a little bit into what is different about j directory so along with the metaphor data rec 3 is kind of like your virtual electrician here you bring this electrician in and he does all this wiring for you and you don't have to be very much work at all so if you've got gobs of existing code or if you look under you and those see frameworks that are below at all and find see code that's kind of interesting to you this has been true in the past and it's probably may well still be true the future and you happen to be a little bit decaffeinated as a programmer and don't want to write all those little methods even if project builder makes it just easy as as you can think the solution is to let Jay direct possibly write those see functions that glue between the native and from the native jni argument type implementation and the sea functions that are being supplied to you somewhere else so we use that for the AWT as I said this is technology that we've been using for a long time a quick time also uses this technology and so you know it's been there before we we know about if you can you can you can count on it as well so briefly how do you how do you get this virtual electrician to do its job so what it needs is the name of the library that contains those key functions you know can't it's not going to go grab an NM the system to find functions for you and you need to tell it which class has those native declaration that's a pretty simple contract I tell it where the library is tell it tell it what what functions you weren't ready for on your behalf and so you have to tell us in these two ways you tell the name of the library and the static string inside that class that has those native methods there are other options as well and then you tell the clot even you hand the class itself to the you know to the constructor of this J direct function so I actually have a little bit of code here show you how easy did you can read the code right the first line is that string J direct underbar mäkelä 10 as value primed eyelids so presumably Prime has this you know very fancy super calc engine kind of technology underneath it you tell you ask a direct and second line second functional line to go ahead and build those those stub functions so you handed crime class now note that this is the prime duck class itself so you're just using that that fancy one that one dot class directive to hand an instance of or hand the class description into J direct itself J direct uses reflection to go find out what methods to write native code for and allocate some see memory rights and key functions in that sea memory jams them into a funky little jni object itself and hands you back the handle to all those gizmos in that thing called that we store in linkage so you actually need to hold on to that object that linkage object because if you don't it will be garbage collected you know if it's garbage collected and you try to access those functions well we're not going to help you with that so the last line of this is the actual method that we're in this and this example tried to do if I would have had more lines on this slide I would have done the four methods that were in the earlier example so anyway j directory is in this example absolutely simple to use so you ought to note though that j directory is a rather interesting set of technology so you can have there's a slight difference in the types of arguments you can use with it in j directory you can use scalars and array an array of scalars although arrays of boolean dry understand aren't quite there you cannot pass objects however we don't have any way to really map objects in any intelligent fashion what we're doing under the covers is in the case of arrays is we're actually copying the bits out of the runtime into a privately allocated memory rummaging with it and then when we're done with the copying it back in this is the contract jni has for gaining access to a rage so we haven't seen issues with that even for quick time so it's just a note for you as I mentioned earlier there are different ways to name different libraries if you put that same string inside of an interface and then your class implements that interface J direct will do reflection on the interfaces and find those strings and so you can have several libraries that held the implementations of a set of methods that are described in one class you can write code that runs on jay direct to in the 118 environment on mr j in that environment we that we tune the run time to look for a very magic interface and so if you extended that interface we knew how to we do to call the call the invoker or call the callback sure you do that that glue bindery we will be writing a text note for that and so if that's important to you then it is possible that's not too bad again that last line or told you about you have to hold on to the results of that in order to keep it working so a final note you know one of those frameworks underneath that might be interesting to you is the carbon framework the toolbox has now been carbonized and awt uses the carbonized toolbox the contract there is that you cannot go rummaging inside a lot of carbon objects as you used to be able to do on mr j so you have to use the accessor functions just like everybody else does so in this case we have an example where you have to use the accessor functions instead of going off some magic offset and pulling out the data yourself finally our diagram again what happens when you need to take an entire job environment and put it inside another application that is what we used to do with Jay direct or Jay manager too and we have a successor to that and we don't have a name for it yet I guess it's the embedding the story for mac OS 10 and the person who can best speak to this is none other than yes so I'll call him back up to stage and see if he can run you through some of these examples and he will obviously speak more knowledgeably about it than I will thanks so we talked about wiring job into your carbon application little asterisk there because we would eventually like this to be able to work for cocoa applications as well but the technology to do so isn't quite available yet the first the bad news for all you Jay manager fans Jay manager is not supported on OS 10 the good news is that well it's actually good news that she mounted she's not supported because it's a very complicated API it requires you to do a lot of work in your application everybody who did it ended up doing it in kind of slightly different ways and causing incompatibilities for us and our developers which is actually kind of our fault in the design of the API so the good news is that we have a new API and the API is very simple because we now have a modern we don't have a much more modern environment to work in we don't have the same kind of limitations we did back when we did Jay direct to first there are a couple of different pieces to what you need to do first you need to obviously get java running and you use absolutely cross-platform standard jni in fact the j no indication api to do that you need to describe the kind of code that is that you want to embed in this kids talking about applets is that the primary target is the web browser or other application that can show applets you can also use other kinds of code you fill out a fairly simple struct with the information about the location or the tense of the applet then you create a Java control or a job a window yes we are using the control manager now so for better for worse the control manager is the sort of component story for 10 at least in carbon and we have a job of control that you do like going create Java control and that is mostly all there is to the story once the control is there you need to be a good host to control you need to make sure that your controls and particularly the Java control get all the events that they need and I'll talk about that in more detail in a minute we have a sort of preview of this in DP for which is mostly just a header file you can look at and start thinking about this much promised future add-on release will have a functional implementation of it so the first step as I said just use Jay and I to start up the Java Virtual Machine and this is exactly how you do it we we type this in ourselves we could have torn it out of sun's java tutorial or any of the jni books that are out there at your favorite computer bookstore first of all we set up this Java VM in it arg structure which is what tells the Java Virtual Machine all the different parameters it needs for starting up things like the default heap size stack size things like that and we don't care about weird can use the default so we fill in the version number and the struct and call Jay and I get default Java VM in it argh and that's going to fill out the structure for us with the default values and if you wanted to tweak some of those values to increase the heap size or something like that you could do it after that then all we need is Jay and I create Java VM that's going to initialize the Java VM for us and start it up and the it returns us a JVM structure Java VM structure which is rarely needed and a jay n IM structure which is always needed for jni calls so we need to save that one off second step is making this magic struct that tells our embedding code where the code you want to run is in this case we have a simple example of where we're giving it a file path to a local Apple if it's in our hard disk so we create this emerging applet descriptor struct we do a bit of core foundation magic to create a URL given a a unique style path and we null out the rest of the structure if you wanted to you could also use a real HTTP or whatever URL to specify that you can also provide a different code base and doc base you can also pass in the contents the raw contents of the applet tag or a pre parse Set of apps of properties the latter will be more useful to you if you're a web browser and you've already been parsing the HTML the second step then is to take this mrj code descriptor and stuff the Apple descriptor into it applets being only one of the ways that you can use to tell which kind of code you want to embed finally then we embed the control we need a bounds rectangle that will fill out and then we call a create Java control passing in the jni environment the window we want to control to go into the bounding box and then the code descriptor and as usual the last one is an out parameter that actually returns to control back to us and that's it so behind the scenes the embedding library is going to start up an applet context go out and load the applet start up the appropriate threads forward send at the events and do some magic stuff with awt so that the the frame that the applet gets embedded into is actually the control in a portion of your window so you need to be able to run controls and for the most part this is kind of Java program or Mac programming 101 type of stuff there's actually really no extra work to handle windows that come up if you if you want the Apple to come up in a window or if the applet opens up its own windows after the fact they simply pop up as windows in your lair and the nice thing is that carbons event manager does all the work of making sure the events for those windows go to those windows and not into your event loop so about all you have to do is make sure that you don't step on them you don't inadvertently when you're traversing the window lists go and assume that it's one of your windows and you know dereference the rest con and cast it to your struct and try to do stuff with it just pay attention to which windows are years and which ones aren't the same deal goes for menus if an AWP window is active it will append menus to your menu bar and it will remove them when it becomes inactive and if you go around / versing the menu bar for whatever reason you need to pay attention to which menus belong to you and which ones don't and there are some access or functions in the API that will help you determine whether or not this menu where this window belongs to Java for control you need to make sure that all the relevant events are dispatched to controls and in Mac programming 101 back in the nineteen eighty four days the only kind of things that controls really got were clicks because controls were just limited things like buttons and check boxes with the appearance manager and the last couple years things have gotten a lot more sophisticated and controls canal they can now have focus they can get key presses they can do curse or tracking while the cursors over them they can do drag and drop so there are several new calls in the controls dot H that are there to allow you to pass those events into the control it isn't that much more work to do there's about three more places in your event loop or you need to do the right kind of control stuff and the appearance manager SDK has all the sample codes for how to do that sort of thing but the real real way to do it the good way to do it is to have your app adopt the new carbon event model if you tens any of the sessions on that yesterday you'll know that the carbon event model is incredibly cool and it's just a vast step forward for the way Mac applications work the vents are dispatched to the object that they're intended for it's a lot more like you're used to with Java programming where if there's an activate event for a window well the windows is it the windows event handler will get that event if there's an event for our control the controls of that handle will get that event there's no need for the applications event loop even to get involved so you get all this stuff basically for free for using the carbon of that model you put the control on your window and just runs itself at the bottom here I have a couple a list of some of the new appearance functions that you'll need to use with an old style event loop create route control handle control click etc and if that's the way you're doing is that I encourage you to go out and look at the control manager documentation that came out with the appearance manager and with OS 8.5 to describe pretty well in there so now I get to be my own demo boy and run the demo back here on this machine so I wrote it out pretty quickly that shows off this stuff and since I wanted to do pretty quickly I used to carbon event model and what I ended up with and probably a little too small for you to read this is four pages of code of which the first about two and a half or some kind of generic stuff to [Music] create a new window add some event handlers to the window create a text controls we have a text field where you can type in the applet path add some listeners to that create a push-button so we can push it to run the applet very standard carbon event stuff we have a window listener function the text control listener function and then down here we have the meat and do this all fits on one screen with a little pipe we first have yeah down here we have the jni indication stuff and this is almost exactly as it appeared on the slide earlier we call Jay and I get default vm in it args and then Jay and I create Java VM and again the stuff that shows the applet is almost exactly as it appears we create a CF string rep for the path the CF URL ref and then we call create Java control and again i'm mostly showing the source code just to point out how small this is the four pages of code it took need a very short amount of time to write and the application itself looks like this so being at as carbon events application we get all these behaviors for free window dragging window resizing etc text field runs we will run draw test another one of these silly sample applets push the Run button and here's our apple we can resize the window everything redraws itself as you'd expect movable this applet doesn't happen to do text input that that works as well all in a four page app so it think offense a lot simpler than using J manager and as I said in the past only a couple of applications ever used a manager partly because it was just rather intimidating how to rather steep learning curve and compatibility problems we hope that in the future since this new API is so much easier that more applications will think about embedding Java thing to do though one more thing yeah the debugging demo did you plugin will not work for demo gods were angry or we will not be able to build the application so we can't run it ah I tell you ours were the work young re ready to swear in front of all these people did debugging work I solemnly swear that debugging worked we were able to set breakpoints yay we were even able to step through the code & view stack traces it was good it truly is good project builder which is the intro session is going on right next to us but you're not seeing you've seen a little bit of project builder here project folder is really looking good we know how to hook up debugging inside of there debuting is really doing a great job making all that happen and we work really hard to try to get that here to show you because we honestly don't believe that J to be is the way for you guys go out into bug Java stock so well there's nothing like if we don't have worrying okay yeah we're all bow and we're just totally living on the edge now but you know if we fall down our pants leave apologize real followed us so if we can run this thing it so Dave Seiss it's a great point now you while you're running it's in project builder I just hit run any kids how would you guys yeah ya need to put stuff Java debugger see if there can see us okay from do we have break points that instead of waiting to connect so it's the speaker for running hot spot isn't it no yeah you're right sure that'll help she's got a run job on orders of the bug Java it turns out he were loading it lazily that wasn't good was it okay forget I tried it worked great before ok back to the back to the side ok so basically we know that we've been postponing a lot of questions until now so we're trying to leave a little bit of time for some questions here so you should remember Java is you know wired into the walls of Mac OS 10 you shouldn't be shocked at what you find on DP for because we're going to make it better and I'm going to point everybody to Alan Samuel to make sure that you know that he's the guy you need to ask about all the updates I mean after him so the take-home exam we had a pop quiz at the beginning well I want to just carry the metaphor going free to take home right a Jay and I enable java class debug your code using it profile your code make sure it runs fast throw away the jni stuff use j direct instead and finally some some bedding is so simple i mean it looks like almost I could program that and well anyway I don't do GUI so that it looks simple enough for me to use so it ought to be simple enough for you guys to use roadmap we only got one other Java session that's this year at wwc and immediately follows this one so if you have marketing style questions you have you know kudos for us or non kudos for us take those to the feedback forum to find out you know where we fit in relationship to the rest of the world of Java and things like that for this session if you've got technical questions about how something happens and things like that what I'd like to do is call up members of the Java team you guys can hit the mics and ask us anything else you want you