I notice a src.zip file containing some Java source bundled with the standard JDK install. When unzipped I notice C source files for the Java launcher, etc.
However, when I download the Java platform source from download.java.net/jdk6/source, I see a different folder structure and different files being laid down. Whats the difference between the two?
I want to recompile the Java launcher (rebuild java.exe using java.c). I can only find java.c in the src.zip file that is part of the JDK but not its dependencies. They seem to exist in the full source code bundle of the JDK. However, java.c itself seems missing in the full JDK source bundle. This is confusing to me.
Can someone please clarify the difference and how best to go about rebuilding only java.exe?
I assume that you are missing jni.h, etcetera. Take a look in $JAVA_HOME/include for the missing header files.
"The difference" is that the JDK that you download from the Oracle website is not OpenJDK. Rather it is based on the OpenJDK codebase, with a bunch of extra proprietary stuff.
It is your choice which one you use.
Related
I am using Code::Blocks with wxwidgets and I have include and lib folders under Document\wxwidgets. I am very new to c++ libraries. In Code::Blocks project initialization, I entered the location for wxwidgets. Then in setting/global enviornment variables I entered in base the Document\wxwidgets again. Still, I am not able to run the app. It shows the error in the include/wx/platform.h file where it says
C:\Users\Programming coder\Documents\wxwidgets\include\wx\platform.h|148|fatal error: wx/setup.h: No such file or directory|
I am not able to solve this and would appreciate some help. Also I checked and the wx folder does not seem to be there in the location. I don't know if that is normal.
Also, I downloaded the headers(include) from the wxwidgets github repo download page, wxWidgets-3.1.1-headers.7z. Any help appreciated.
Also, I am aware some questions exist already, but their problems are in different because most are using linux. Also I am using Code::Blocks IDE.
You need to build wxWidgets itself before building the applications using it. Its build process will create the setup.h file which is currently missing.
Note that, in principle, you could also use precompiled binaries, but in this case you must use exactly the same compiler as was used for compiling them, i.e. TDM gcc.
I have a Cocoa application that uses OpenCV, TBB, boost and some other libraries which are installed in my system. How do I create a package that has all this inside so that customer doesn't have to install anything besides just copy/paste my package?
At the building stage they are referenced via .dylib .
Is it possible?
Where I choose in xCode Product\Archive it will only export the app itself.
well, after a lot of reading I could not find an easy solution. Maybe is there, but I didn't have more time to search for it.
So instead I wrote a small application in C++ that uses otool and install_name_tool utilities to analyze needed required libraries and copy them into the bundle. Is located here https://github.com/integral-llc/libb . Keep in mind, it was made for personal use, but can be easily changed for anything else.
It worked perfectly for my case. It found all needed dependencies for OpenCV, boost, TBB.
if you have better tools or ideas to improve current one, you are more than welcome to say.
I have written a simple application using the GPhoto2 Framework, and this works so long as the framework is in the location where it was originally compiled. I would like to move this inside the app bundle, though, so it does not need separate installation, so I need to make it work relative to this main executable.
Unfortunately the framework is not an Xcode project. It uses a script to build, so I cannot simply change the installation directory build setting, which is the solution that I have frequently seen while searching for an answer. Being quite new to Xcode and Mac programming it is also beyond my abilities to know how to convert the framework into an Xcode project.
The other advice I came across was to use install_name_tool to update the library ID and dependencies, replacing the absolute paths with ones of the form "#executable_path/../Frameworks/GPhoto2.framework". The framework is not a single binary, but contains a number of .dylib and .so libraries, but updating all of these has only been half successful.
I have set Xcode to copy the framework into the app bundle when it builds it. Then if I remove the framework from its originally compiled location the application fails to load, with the report generated by OS X saying the libgphoto2 library can no longer be found, as to be expected.
If I then use install_name_tool to update the references in all of the framework libraries inside the app bundle, and also in the app binary itself, then the application will load but fails to find any camera connected. Using otool I am able to verify that all references have correctly been changed.
But if I replace a copy of the framework to its original location it then works properly again, recognizing connected cameras, regardless of whether that framework uses relative or absolute locations. Clearly it is still looking at this location despite loading. I have even tried removing each of the individual library files from the framework in its original location in turn to see if the problem was just the result of a dependency in of these, but no matter which is missing the app will not work.
Incidentally, if I build the app using an updated version of the framework, it fails saying it cannot find the library "#executable_path/../Frameworks/GPhoto2.framework/prefix/lib/libgphoto2.2.dylib"
Am I doing something wrong or missing a step, or is what I am trying to do impossible for frameworks created outside Xcode?
In case someone comes across this future, the answer to my question was that I was doing nothing wrong. The problem was that the .so files were being loaded by libtool ltdl, at it requires absolute paths so these were being set at build time.
I patched the files gphoto2-abilities-list.c and gphoto2-port-info-list.c so that at runtime it would combine the relative library paths with the executable location. As a result I also needed to increase the FILENAME_MAX constant to allow it the mail application to run from, for example, the Desktop. But this, along with the use of install_name_tool allowed me to add GPhoto2 as a framework inside my application without needing any external dependencies.
The final problem of not being able to build my app in XCode with the framework after using install_name_tool remained, but for that I just used the original framework build, then after compilation I updated the references in the copied framework at the same time as I updated the ones in the main executable.
I've been bundling JRE with my app by simply copying the files from $JAVA_HOME/jre to my app's distribution. This may be against the spirit of Java, but it reduces potential problems by ensuring that my app runs on a version of JRE that it was tested on (including the bitness; I use some JNI which requires that the JRE is a 32-bit version).
It works fine, but the whole distribution is somewhat big, so maybe some unnecessary files could be left out? Indeed, $JAVA_HOME/jre/README.txt contains the following advice:
The files that make up the Java SE Runtime Environment are divided into
two categories: required and optional. Optional files may be excluded
from redistributions of the Java SE Runtime Environment at the
vendor's discretion.
The following section contains a list of the files and directories that
may optionally be omitted from redistributions with the Java SE Runtime
Environment. All files not in these lists of optional files must be
included in redistributions of the runtime environment.
...When redistributing the JRE on Microsoft Windows as a private
application runtime (not accessible by other applications)
with a custom launcher, the following files are also
optional. These are libraries and executables that are used
for Java support in Internet Explorer and Mozilla family browsers;
these files are not needed in a private JRE redistribution.
What puzzles me is that the list of optional files includes, among others:
bin\java.exe
bin\javaw.exe
bin\javaws.exe
How can java/javaw.exe be optional? How am I supposed to start a Java application without them? Apparently I don't know something (likely), or the instructions are simply wrong.
When redistributing the JRE on Microsoft Windows as a private application runtime (not accessible by other applications) with a custom launcher, the following files are also optional.
If you embed the JVM (by linking against its shared libraries) in your own application, you do not need the standalone launcher executables. I think Eclipse works that way, for example.
If your app uses the java executable (via a batch file for example), then you need them, of course.
While this doesn't strictly relate to the question, for whole-program (or whole-platform) optimization of removing "un-needed code", I have found ProGuard to be a good tool. YMMV.
I want to compile jdk itself. I mean, I want to modify String.class in jdk to see created string objects in the system. Is there any way to modify classes in the jdk? When I try to modify source by modifying rt.jar, I got the error.
java.lang.NullPointerException
at java.util.Hashtable.put(Hashtable.java:394)
at java.lang.System.initProperties(Native Method)
at java.lang.System.initializeSystemClass(Unknown Source)
Probably there is a signature problem.
That doesn't look like a signature problem. It looks like you changed something that's causing Hashtable to dereference a null pointer. Review the change you made and see why it's doing this. Recall that Java keeps internal references to String constants in some conditions. I'm guessing you broke one of those.
Is there any way to modify classes in the jdk?
Well, you can download, modify and build the OpenJDK releases of Java 6 from source. There's information on how to do this on the OpenJDK site.
But beware that changes to low-level Java classes (such as String) can have effects that are hard to a non-expert to understand. And the consequence could well be a JVM that fails in a way that makes println or printStackTrace() inoperative.
There is maybe another way: you download java.lang.String original source, doing your modifications and compile only this class.
When you start your main programm be aware when loading classes: first load your String class then the java runtime classes. Refer to the java manual and the -Xbootclasspath/p options to do it in the proper order.
When installing a JDK you may choose to install the sources as well. Do so. Or download the sources separately. Then
expand the src.zip and get the String.java file.
create a new project containing the String.java in package java/lang.
change it accordingly to your needs.
just compile it.
put the class into the bootclass path of your JDK. See More infos on Bootclassbath.
run your app.
java -Xbootclasspath/p:<changed String classpath> -cp <regular classpath> <your application main class>
But changing the JDK might not be a good idea and you are not allowed to ship a changed JDK (at least up to 1.6) due license restrictions.
And yes, your problem is most likely somewhere else. Remember select isn't broken ;-)