I have deploy my java code on AWS cloud, when I compile it on windows through terminal, I just have to use the command.
javac mainApp.java
it automatically create .class files of all other classes, lets say I have another class
class newProcessClass
who's variable is in mainApp.java, on EC2 when I compile it, it is giving me the error
error: could not find this symbol
newProcessClass npc = new newProcessClass();
same for the other classes. how can I compile it, and run it.
According to your description, I think that might be caused by classpath issue,
So please make sure current path(.) is under your classpath.
You can do this by type the follow into your terminal(pay attention to the little dot please!)
export CLASSPATH=.;$CLASSPATH
If you would like to persistent this setting and avoid set this everytime, you'd better add it to your .bashrc file.
And then when you run the class via java command, please also specify classpath as below
java -cp . mainApp
I recommend use Maven for the life cycle for application java and when you compiled the mainApp.java this action has that compile all file. you can get me more information of error stack?. For other side I think that is best that you use Maven. Best regards
Related
I can't run methods of a library.
My library is in my PATH and also getting loaded without errors by following code:
System.loadLibrary("FTDIInterface");
But the functions are not working.
I get the following exception:
Caused by: java.lang.UnsatisfiedLinkError: Messgeraet.src.net.sf.yad2xx.FTDIInterface.getDevices()[LMessgeraet/src/net/sf/yad2xx/Device;
at Messgeraet.src.net.sf.yad2xx.FTDIInterface.getDevices(Native Method)
at Messgeraet.src.Emu.EmuConnection.<init>(EmuConnection.java:22)
at Messgeraet.src.Emu.EmuModel.connect(EmuModel.java:27)
at Messgeraet.src.JavaFX.FXController.connect(FXController.java:112)
... 62 more
I am using eclipse. In IntelliJ it is working fine and I also got another eclipse project that includes the library without any problems.
Why it can't run my method FTDIInterface.getDevices?
Your package seems off; Messgereat.src sounds like you have a project dir named Messgereat, within you have a folder named 'src' with your java sources, and you've misconfigured your build tooling; the right package name sounds like it should be: package net.sf.yad2xx;, but due to a misconfigured build it wasn't working and you decided to fix the problem by updating your package statements, but that broke your JNI bindings.
The solution would then be to undo all the changes you've made to your package statements, and fix your build script instead.
Alternatively, if you really do intend to use that bizarre package, then make sure you have executed javah with the exact same build setup and use that as a basis for your JNI code. If you've done that, include the exported symbols in the library as the comment by #user2543253 suggested.
NB: It's a bit odd that your loadLibrary call works at all; PATH has nothing to do with it, but presuambly then your library so happens to be located in a place that is listed on your librarypath, which is the system property (of the VM, not of your OS) named 'java.library.path'; you set it with e.g.:
java -Djava.library.path=/path1:/path2 -cp /path/to/dep1.jar:/path/to/dep2.jar com.foo.Main
because of this confusion it is also possible that some different native lib file also named FTDIInterface is being loaded instead of the one you think is being loaded. If you want to be certain of what is being loaded, run System.load("/absolute/path/to/the/dll-jnilib-or-so-libraryfile.so"); - then you know for sure.
I'm doing some basic java homework for a class on my new laptop - issue is, I can't seem to get the program to compile and run from my batch file using the directions the instructor gave me.
I've set the Path variable to my JDK inside the Environment Variables settings.
My program is a simple shipping program to keep track of shipment information - I have the program working flawlessly in NetBeans (which our instructor advised us to use for developing the code), but he's going to be testing them using batch files, so we're also advised to test them on our systems with one we create prior to turning them in - pretty straightforward.
Issue is, I cannot seem to get this to work. I've never done it before, but I've used .bat files to compile and run C++ programs, as well as using makefiles on a unix system, so I feel like I'm absolutely stupid for not figuring this out on my own, but none of my searches have returned any fruitful solutions that help at all.
My program consists of 3 .java files:
Shipment.java - an interface that contains abstracted methods that are implemented in the ShipmentHW1 class
ShipmentHW1.java - a class that implements the abstracted methods from Shipment and has constructors, etc to create a usable object
TestShipment.java - the main class of this program, which utilizes and creates ShipmentHW1 objects based on preset parameters. This is super duper basic stuff here, and again, it runs perfectly fine inside the NetBeans IDE.
The instructions given to us state to have the batch file inside the package directory (which in this case I've set aside a seperate folder on my desktop titled "shipping", which is the package name - shouldn't be any issues there), where the 3 .java files are located as well.
They say if you don't need to explicitly list the path to the JDK, then you can simply have
javac TestShipment.java
java TestShipment.java
pause
Afterwards I get errors talking about how it "cannot find symbol Shipment s = new ShipmentHW1();"
I've tried adding imports, but since they're in the same package it shouldn't even be an issue.
Directory path is
C:\Users\X\Desktop\shipping
All 7 files are contained within:
TestShipment.java
TestShipment.class
Shipment.java
Shipment.class
ShipmentHW1.java
ShipmentHW1.class
doHW1.bat
Does anyone have any idea? I can provide more information if I've been too vague
Also, I'm on Windows 8 if that makes any difference
Solved
Batch file now reads
javac TestShipment.java Shipment.java ShipmentHW1.java
cd ..
java shipment.TestShipment
pause
and it works like a charm. Anyone have any ideas why I had to call the package.class instead of just compiling it regularly?
Try doing
javac TestShipment.java
java TestShipment
pause
Without seeing the contents of TestShipment.java, I'll assume you have some dependency on the Shipment and ShipmentHW1 classes. As such, when you execute a program that uses the TestShipment class, you need to have the .class files for each of the three (and any other dependencies).
So you will have to compile Shipment.java and ShipmentHW1.java as well before running your java command. If they are in the same package, you're good, if not, you will have to specify an appropriate value for the -cp option.
When running java with a class name, you need to specify the fully qualified class name.
If your .java files are declared to be in the 'shipping' package, then you probably need to be running java from the parent directory of 'shipping', e.g.
cd <path>/shipping
javac TestShipment.java
cd ..
java shipping/TestShipment
I found a traffic light simulator called Green Light District
the file I download included and explanation of how to build the project
and it says the following
Extract the archive to a certain directory,
In that dir do javac gld/*.java
In that dir do java gld.GLDSim
I know * means all but...
first I want to know am I able to compile something like *.java
this is a link to the simulator , if some one can tell how to compile it , it would be really nice
http://sourceforge.net/projects/stoplicht/
The issue occurs due to the fact that "enum" became reserved word in Java 1.5+, so it can no longer be used as a name for variables/methods/classes, but GLD uses enum as a name for some variables.
Once the name is changed - project will compile.
Alternatively one can try to compile it with compiler setting source version 1.4 - this should probably also work, but I suggest to simply rename all variables named enum.
Basically, all the code is in the folder called gld. You need to compile all the .java files inside it. After that, you run the main class gld.GLDSim.
Had the same problem.
You should use Java 1.4, this simulator is quite old, hence uses an old version of Java and some preserved words in more advanced Java versions.
I am using the code from Rome's tutorials page http://wiki.java.net/twiki/bin/view/Javawsxml/Rome05TutorialFeedReader . Also trying this one: http://wiki.java.net/twiki/bin/view/Javawsxml/Rome05TutorialFeedReader
Compiling works, but I'm not sure how to run these examples. Why I just type java FeedReader or java FeedAggregator into the command line, I get the error:
C:\projects\freshmeat\src>java FeedAggregator http://freecode.com/?format=atom
Exception in thread "main" java.lang.NoClassDefFoundError: com/sun/syndication/f
eed/synd/SyndFeed
plus the large block that follows this error
Why is this happening, how do I fix it and try these things out? How do I get something to work with Rome!?
You need to include rome in the runtime classpath (in addition to the compile-time classpath)
java -classpath lib/rome.jar FeedAggregator ...
The samples you are trying to run are in the package com.sun.syndication.samples. You say you are a complete beginner, so, to make things simpler, I would recommend that you remove the line beginning with package in each of FeedReader.java and FeedAggregator.java. Recompile the classes after removing their package directives.
Then, to run these classes, make sure you're in the same directory as the class files FeedReader.class and FeedAggregator.class that javac created. Then, try running:
java -cp c:\projects\freshmeat\libs\rome-1.0.jar;c:\projects\freshmeat\libs\jdom-1.0.jar;. FeedReader
(and similarly for FeedAggregator.)
Note also that I've added the current directory, ., to the -cp attribute. Without this, the Java virtual machine won't know that it has to look in the current directory to find your FeedReader and FeedAggregator classes.
If you were to reinstate the package directives, you'd find the class files FeedReader.class and FeedAggregator.class would be created inside a directory com\sun\syndication\samples when you compile their sources. To run the class files from this location, you'd use a command line such as
java -cp c:\projects\freshmeat\libs\rome-1.0.jar;c:\projects\freshmeat\libs\jdom-1.0.jar;. com.sun.syndication.samples.FeedReader
and you'd run this from the directory containing the com subdirectory, not the directory that contains the class files.
More information on packages in Java can be found here.
I'm new to java development, I just want to use javac for my build system. I'm using java to add a feature to a program someone else wrote, specifically involving GeoTiff images.
I found a class online that I would like to use, however I'm having trouble building the class, no matter what I do I get this message:
javac GeoTiffIIOMetadataAdapter.java
GeoTiffIIOMetadataAdapter.java:11: package com.sun.media.imageio.plugins.tiff does not exist
import com.sun.media.imageio.plugins.tiff.GeoTIFFTagSet;
I'm on RHEL5, so I installed the package I thought I needed, jai-imageio-core.x86_64. But the problem persists. I think that I'm not setting some variable corrently (like -sourcepath or something). I would appreciate any help.
You need to include the jar with -cp or -classpath.
So your compile would be like java -cp "<location to jai_imageio-1.1.jar>" <your java class> .
I think you need this jar file.
You can read more about javac here.
Find out where the package installed the jar file with the class you want to import, and add it to the javac commandline in the -classpath. (You then also need to include it in the classpath when your plugin runs; how to do that may depend on the program it plugs into).
I think that I'm not setting some variable correctly (like -sourcepath or something)
This tutorial briefly introduces the usage of environment variables in Java: PATH and CLASSPATH
This one seems to be the most popular answer to various classpath related questions I've seen at online forums: Setting the class path.
To avoid "blind recommendation" I quickly skimmed through it before adding to this answer and, well... it really covers most of what one needs to know to deal with classpath. Pretty good; the reason why I didn't look into it before is that there always has been some guru nearby who explained stuff to me.