Scanning classpath with ant build yields different results - ant

I have an Ant Task that scans the entire Java project class path for certain class files.
The method is preety naive:
A File object is created at the root of the search path and then there's a recursive search for class files.
For each class file, use the CURRENT ClassLoader (this.getClass.getClassLoader) with loadClass() to load the class.
Check if the class loaded is an instanceOf a certain class.
The weird thing is, that if I run my build in debug-mode with "Separate JRE" chosen in the JRE launch tab, the build takes around 8 seconds.
If I select "Run in the same JRE as the workspace" the build takes around 40 seconds.
My project also includes 10K of class files or so.
In debug mode, pausing the build shows clearly that most of the time is wasted at loadClass().
My guess is that "Separate JRE" somehow causes the build to run with a minimal class-path so the class loading process is faster..? But it doesn't make much sense..
Does anybody have a lead on the subject?
Thanks in advance.

Related

:erlang.load_nif/2 finds shared library file inside original project but can't find it if the project gets imported

I've build a small elixir application that uses NIF functions to execute some c++ code.
The nifs are loaded via:
def load_nifs do
:erlang.load_nif('<relative_path_to_lib>/<lib_name>', 0)
:ok
end
and this works fine.
Now I want to integrate this app into another project. The problem now is that load_nif throws:
Failed to load NIF library: '<relative_path_to_lib>/<lib_name>.so: cannot open shared object file: No such file or directory''
although nothing has changed. I checked the deps folder and the shared library files are exactly where they are supposed to be, so the dependency seems to be loaded correctly. I also tried putting the .so files into the same folder as the module that calls load_nif (and omit <relative_path_to_lib>/) as well as providing an absolute path, all to no avail.
Any help is appreciated, Cheers.
Relevant info regarding my system:
OS: Ubuntu 22.04
Elixir version: Elixir 1.13.0 (compiled with Erlang/OTP 24)
Update:
The issue does not seem to be that files are located at the wrong place, as it finds the files during the first test run after compilation.
However, the error occurs when I repeat the run. It seems that the error message is wrong, since no files are deleted during the test.
If I repeat the function within one test multiple times there's no problem, so the issue is not created because the NIF function is executed multiple times, but because the test that contains the function is repeated multiple times.
Solution:
I still have no idea what causes this behavior but after putting the .so files into a priv directory and accessing them via
:erlang.load_nif(:code.priv_dir(:<app_name>), 0)
the tests pass.

Is there a way to add native rules to Bazel?

I would like a set of rules from my_package.bzl to be accessible to all BUILD files of a workspace without having to load my_package.bzl in the BUILD files. Basically I want the rules in the package to look like native rules. How can I achieve this?
I was thinking maybe there's a line I could add to one of the .bazelrcs or to the WORKSPACE file of the the project.
This can be achieved by adding a prelude_bazel file at //tools/build_rules:prelude_bazel (this must be a package, so tools/build_rules must contain a BUILD file).
This will be loaded and prepended to all BUILD files loaded by Bazel.
However, there are a few things to consider before going this route. It's currently undocumented, and while doing some searching to find any info on this feature, it's unclear if it will remain a part of Bazel.
It may also have performance / scaling problems. If the prelude were to change (or any of its dependencies), every BUILD file would have to be reloaded, and this may take some time depending on the size of the build graph.

Xcode repeatedly copying bundle resources

I have a question regarding Xcode and bundle resource copy.
I'm currently working on a project with a large asset library. So, a clean install, or a change in a bundle resource warrants a copy of the "new" bundle resource(s).
However, the problem that I'm currently facing is that Xcode is copying a part of my entire asset library every single time that the application is built. This behavior is super weird, since on all the projects that I've worked, Xcode only copied resources if they had changed, or if it were a clean install, or if there was something new that had not been copied before.
In this case however, it copied all the resources on a clean install (expected). However, on every consecutive build, it is still copying some of the files over. Now this is super strange, since none of the files have changed, and it is not copying all the files, only a small portion of them. One more thing - if I run the same app, with the same configuration on the simulator, the copy DOES NOT happen (moar strangeness).
Is there some setting that I can change, or maybe a flag that I can include that might prevent this from happening?
Thanks in advance for the help!
Cheers!
It's been a month since this question's been asked, and I've managed to find a "sort of workaround" solution.
Now, the reason I'm putting this in as the accepted answer is primarily because no other answer/solution has been posted as of writing this. If anything better is posted (or if I have an update), I'll be sure to mark a better answer as the accepted one.
Either ways, this "workaround" will work if you have a super large set of assets that don't change over consecutive builds.
The project I'm working on has a lot of audio and video files that have already been prepared, and aren't going to change (other than the occasional re-recording or something along those lines).
So, as my question states, Xcode was copying a subset of the resources. Ideally, once a resource has been copied (and there are no changes to it), it is not re-copied (at least not supposed to be re-copied) over consecutive builds. In my case, it was getting copied during every consecutive run, causing my total build to start time to be around 15 ~ 20 mins. I'd also like to point out that regardless of whether we used "run script" in the build phases or whether we had the media in our Xcode project, we were facing the same issue.
Solution:
What I did was I cleaned my project, deleted the app, and did a fresh install. So, the first time, it copies ALL the files over with the app. Also, the assets directory is NOT in my Xcode project. We've added a "run-script" phase, wherein we run rsync to copy the media from the media folder, over to the app, during every build.
Now, once the App has finished doing a fresh build; it would have copied over all the required media files.
Then, REMOVE/DISABLE the script, perform a Clean in Xcode (command + shift + K) and run the project again. This time, since there is no script being run, and since Xcode has performed a clean, wherein now it thinks that all it needs to do is re-compile the binaries, it builds super fast. Since I've NOT deleted the App, the media folder is still in my app, and my build to start times are now around 30 seconds ~ 1 minute (this includes sandboxing and code-signing). Code-sign and "sandboxing" the application still takes time, but this is waaaay better than having to wait 15 ~ 20 minutes every time I hit run. :)
Hope this helps!
I've got very similar situation. Also, I have 6 000 resources in my app, and even listing some of them (not copying) was a bit slow. I've found another workaround (very similar to yours, but a bit easy to perform). It was inspired by your one, so thank you very much!
I copied the target of the project, set its bundle id as the original one (it was automatically set with ${PRODUCT_NAME} from build settings) and removed all the resources from Copy Bundle Resources section. First time (after removed from device app) I need to launch the original target with its resources, but then I can build the copied target while resources are still on device.
Some advantages:
it's very easy to switch between both targets
no need two write any scripts (that was purpose I did not use your solution)
Fun with numbers:
58 seconds from "Cmd+R" to loading screen appearing with bundle resource.
20 seconds for the same interval with empty "Copy Bundle Resources" section. Not so good as yours improvement, but still makes difference.
Hope this helps too :)

TestNG [Error] Cannot instantiate class if testng.xml having more than 6 classes (in command prompt)

As per my project, having 15 classes in testng.xml. When i run testng, i got OutofMemory exp.. so i given more heap memory (in eclipse) then its working fine.
I added build.xml file to my project and when i try to run through command prompt, getting :TestNG [Error] Cannot instantiate class (for 7th class).
Upto 6 classes its working fine.
I tried by allocating memory max 1548m to jvm in command prompt but no use. There is no Xmx option in ant bat file just like eclipse.
Look at the error message carefully and find out which class TestNG can't instantiate. Most likely, that class doesn't have a public, parameterless constructor. This has nothing to do with the number of classes in your testng.xml.
Did you profile your test , Most of the times for lager suits memory cleaning is a important. Use some tool like jprofiler and see whether there are any memory leaks in your tests.

BlackBerry Screen Shot Utility ... Torch 9850 ... a how to guide on creating your own capture script/tool

I am providing this for everyone to hopefully save you some brain damage in finding this yourself.
As I'm working on a BlackBerry project that will run on various devices I ran into an issue grabbing screenshots from the handset (including the Torch 9850 ... not quite as good as my iPhones or my Android EVO or Infuse, but much better than the Storm and finally starting to look like a real smartphone - great performance and battery life too).
Normally I'd use my trusty BBScreenShooter and everything would be fine, but it kept crashing when attempting to capture images on the 9850. I posted a couple of requests for help on this site, but nobody could tell me why my BBScreenShooter was crashing or why I'd get "Retrieving screen <active> data ... Error: buffer too small" when using RIM's JavaLoader utility directly.
For those who didn't know BBScreenShooter delegates the "heavy lifting" to JavaLoader to grab the images.
With the help of Mark Sohm (easily one of the most knowledgable BB guys I know walking the planet) he asked me to verify I was using JavaLoader that is included in the v7 SDK. Turns out I wasn't. Good catch Mark, and thanks!
From the looks of things it appears the earlier versions of the JavaLoader utility have byte[] buffers they use for image capture that are hardcoded ... and too small.
So, for all those who need to capture screen shots from RIM's new 480 x 800 based handsets I have included a quick "how to" guide to help you get productive ASAP.
Step 1 - Make sure you have the v7.0 SDK downloaded (doesn't have to be installed, though I cannot think of a good reason not to). For Eclipse users:
Step 1a) Go to the Help menu
Step 1b) Install New Software menu choice
Step 1c) Add the "BlackBerry - http://www.blackberry.com/go/eclipseUpdate/3.6/java" items in your "work with" field.
Step 1d) Under the "BlackBerry Java Plug-in Category", look for the "BlackBerry Java SDK v7.0.0.X" checkbox and click NEXT.
Step 1e) Accept the license agreements and continue the download and installation process.
Step 2 - Go to the installation directory for your newly added SDK. We're going to grab a copy of the path to the JavaLoader utility and use it within a BAT file that will automate the capture and naming of screen shots. This will be found at /plugins/net.rim.ejde.componentpack7.0.0_7.0.0.28/components/bin/JavaLoader.exe
Step 3 - Create a folder you'd like to use to save screen captures. This will also hold your BAT file as the BAT file is specific to this particular project.
Step 4 - Create the BAT file. In my example here I keep all my IDEs, SDK, ... effectively all development environments on a different hard drive than my OS. I keep these on drive D, but modify your BAT to reflect the location and needs of your configuration.
Step 4a) It's important to turn the echo off, otherwise you will probably be unable to use the icon on the desktop to launch this script/utility.
Step 4b) If your BAT file is running locally (same folder) as JavaLoader then this step will be unnecessary. On the other hand if your JavaLoader is on a different hard drive and tucked away deep in folders then you'll have to "change directory" to get to it. Notice the "/D" switch that is used with the "change directory - cd" command so that we can change drives and paths in the same step.
Step 4c) As I like to use timestamps for part of my file names ... set local variables to represent the current date and time.
step 4d) The following "for" statements parse out the current date and time from my Windows 7 computer into a format that I want to include as the file names for my screen captures ... file name == BlackBerry_<date image was taken>_<time image was taken>.bmp.
Step 4e) Copy the newly created device screen shot that JavaLoader captured to your target folder and use the file name we've just created.
Step 4f) Now that we've successfully got a copy of the screenshot saved in our desired target folder we can delete the temporary image that JavaLoader created.
Step 4g) I echo a little statement that lets me know it all worked.
Example BAT file:
#echo off
cd /D D:\Program Files (x86)\EclipseBlackBerry\plugins\net.rim.ejde.componentpack7.0.0_7.0.0.28\components\bin
JavaLoader screenshot tempImage.bmp
set timestampdate=%date%
set timestamptime=%time%
For /f "tokens=2-4 delims=/ " %%a in ('date /t') do (set timestampdate=%%c-%%a-%%b)
For /f "tokens=1-2 delims=/:" %%a in ('time /t') do (set timestamptime=%%a%%b)
copy tempImage.bmp "C:\Users\CirrusFlyer\Desktop\<project name>\Testing\Screenshots\BlackBerry_%timestampdate%_%timestamptime%.bmp"
DEL tempImage.bmp
echo Completed "...\<project name>\Testing\Screenshots\BlackBerry_%timestampdate%_%timestamptime%.bmp"
Step 5 - Close and save your BAT file. I kept the BAT in my actual project folder, then created a shortcut and placed it on my desktop. This way I can have my Eclipse up and running and be debugging the application on my handset, and when I want to grab a screen shot simply double-click the shortcut to execute the capture.
This will create screen shots and place them in the target directory: BlackBerry_2011-10-07_1015 PM.bmp, for example.
Step 6 - Your done. Happy coding. Hope this helps.
My next project: extending Eclipse so that I can do screen captures directly from within the IDE the same way I can when doing Android based programming.

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