What are the possible causes of a "java.lang.Error: Unresolved compilation problem"?
Additional information:
I have seen this after copying a set of updated JAR files from a build on top of the existing JARs and restarting the application. The JARs are built using a Maven build process.
I would expect to see LinkageErrors or ClassNotFound errors if interfaces changed. The above error hints at some lower level problem.
A clean rebuild and redeployment fixed the problem. Could this error indicate a corrupted JAR?
(rewritten 2015-07-28)
Summary: Eclipse had compiled some or all of the classes, and its compiler is more tolerant of errors.
Long explanation:
The default behavior of Eclipse when compiling code with errors in it, is to generate byte code throwing the exception you see, allowing the program to be run. This is possible as Eclipse uses its own built-in compiler, instead of javac from the JDK which Apache Maven uses, and which fails the compilation completely for errors. If you use Eclipse on a Maven project which you are also working with using the command line mvn command, this may happen.
The cure is to fix the errors and recompile, before running again.
The setting is marked with a red box in this screendump:
try to clean the eclipse project
you just try to clean maven by command
mvn clean
and after that following command
mvn eclipse:clean eclipse:eclipse
and rebuild your project....
Your compiled classes may need to be recompiled from the source with the new jars.
Try running "mvn clean" and then rebuild
The major part is correctly answered by Thorbjørn Ravn Andersen.
This answer tries to shed light on the remaining question: how could the class file with errors end up in the jar?
Each build (Maven & javac or Eclipse) signals in its specific way when it hits a compile error, and will refuse to create a Jar file from it (or at least prominently alert you). The most likely cause for silently getting class files with errors into a jar is by concurrent operation of Maven and Eclipse.
If you have Eclipse open while running a mvn build, you should disable Project > Build Automatically until mvn completes.
EDIT:
Let's try to split the riddle into three parts:
(1) What is the meaning of "java.lang.Error: Unresolved compilation
problem"
This has been explained by Thorbjørn Ravn Andersen. There is no doubt that Eclipse found an error at compile time.
(2) How can an eclipse-compiled class file end up in jar file created
by maven (assuming maven is not configured to used ecj for
compilation)?
This could happen either by invoking Maven with no or incomplete cleaning. Or, an automatic Eclipse build could react to changes in the filesystem (done by Maven) and re-compile a class, before Maven proceeds to collect class files into the jar (this is what I meant by "concurrent operation" in my original answer).
(3) How come there is a compile error, but mvn clean succeeds?
Again several possibilities: (a) compilers don't agree whether or not the source code is legal, or (b) Eclipse compiles with broken settings like incomplete classpath, wrong Java compliance etc. Either way a sequence of refresh and clean build in Eclipse should surface the problem.
I had this error when I used a launch configuration that had an invalid classpath. In my case, I had a project that initially used Maven and thus a launch configuration had a Maven classpath element in it. I had later changed the project to use Gradle and removed the Maven classpath from the project's classpath, but the launch configuration still used it. I got this error trying to run it. Cleaning and rebuilding the project did not resolve this error. Instead, edit the launch configuration, remove the project classpath element, then add the project back to the User Entries in the classpath.
I got this error multiple times and struggled to work out. Finally, I removed the run configuration and re-added the default entries. It worked beautifully.
Just try to include package name in eclipse in case if you forgot it
Import all packages before using it, EX: import java.util.Scanner before using Scanner class.
These improvements might work and it will not give Java: Unresolved compilation problem anymore.
Also make sure to check compiler compliance level and selected jdk version is same
As a weird case, I encountered such an exception where the exception message (unresolved compilation bla bla) was hardcoded inside of generated class' itself. Decompiling the class revealed this.
I had the same issue using the visual studio Code. The root cause was backup java file was left in the same directory.
Removed the backup java file
When the build failed, selected the Fix it, it cleaned up the cache and restarted the workSpace.
I am new in Cmake thats why I will write story detailed.
I trying to build one lib under windows and that lib depends on other lib. (libmatroska depends on libebml) source libmatroska and source libebml
Fortunately both libs can be build with cmake.
I built libebml successfuly with cmake. And also built binaries using VS studio.
Then I tried to deal with libmatroska:
During first try I got:
Could not find a package configuration file provided by "Ebml" (requested
version 1.3.5) with any of the following names:
EbmlConfig.cmake
ebml-config.cmake
at libebml sources I found EbmlConfig.cmake.
I Type export Ebml_DIR=D:/work/mkv/libebml and try again.
On second run I got:
Could not find a configuration file for package "Ebml" that is compatible
with requested version "1.3.5".
The following configuration files were considered but not accepted:
D:/work/mkv/libebml/EbmlConfig.cmake, version: unknown
And after few hours I am still stuck on it.
I can't understand root of this error.
Is it something wrong with EbmlConfig.cmake?
... or maybe I specified path to wrong *.cmake file?
... or I need to install libebml some how before handling libmatroska?
I will be happy for any clue.
UPDATE:
Here EbmlConfig.cmake context:
include(${CMAKE_CURRENT_LIST_DIR}/EbmlTargets.cmake)
Where EbmlTargets.cmake is file generated while Ebml compilation.
I tried to change path inside EbmlConfig.cmake to global path. But got same error.
Also when I delete context of EbmlConfig.cmake I still have same error.
It looks like "default error when something goes wrong"
in IntelliJ (2016.2 and previous) we have our Groovy classes marked red with the error "class already exists".
I think we can exclude that the cause is the stub-generation, as this is deactivated.
Probably it's caused in our constellation: We have included our compiled groovy (and java) classes in a jar that is registered as dependency.
Dependency MyProduct.jar contains com.mycompany.MyGroovyClass
Our source contains com.mycompany.MyGroovyClass
The error disappears if the dependency is registered with Test-Scope, in all other scopes the error appears.
However, in our structure we kinda have to include the compiled classes in a compile scope, as we want to avoid that each developer needs to compile all classes (I know about the compile in background ability, but we have a constellation that prevents this from working).
We have no errors in com.mycompany.MyJavaClass which exists as well in source and in MyProduct.jar.
Any ideas on how we can solve this?
We've been suffering the same issue, it seems to be that IntelliJ registers the Java class, but also the Groovy class, and because of that it is showing that message (BTW, we are using a Maven Project).
So we ended up by going to the target folder -> right click -> Mark Directory As -> Excluded. Then, this setting will be saved on the IML file, and it won't happen again.
Hope it works for your as well!
Cheers
I'm using gmavenplus-plugin:1.5
After marking target/generated-sources/generated-sources/main as "Excluded", The error disappeared. I even did "invalidate cache and restart", It persists the setting. This is great. Intellij 2017.1.5
We have two ways to fix this issue
Exclude Stub Directory
target folder -> generated-sources -> groovy-stubs -> Right click main folder -> Mark Directory As -> Excluded
Remove generateStubs goal from gmaven plugin
Remove <goal>generateStubs</goal> from gmavenplus plugin
Make sure you Mark the src folder as Sources Root and do the same for the test folder
Then delete the target folder (most likely it's marked in yellow) and don't worry it won't delete any code from your project
If the issue persist, proceed to go to File -> Invalidate Cache/Restart
I'm trying to create an executable jar from IntelliJ.
First I got the Java Security Exception and I changed sqljdbc4-4.0 to unsigned. First problem solved.
Then I got Manifest not found. Added META-INF dir to output. Second problem solved.
Next I got the BeanCreationException (unsolved):
Caused by: org.springframework.beans.factory.BeanCreationException: Cannot determine embedded database driver class for database type NONE. If you want an embedded database please put a supported one on the classpath.
In IntelliJ it is working.
I think the resources are not in the output. (application.properties, ...)
In which way do I add the resources or where are they stored in the jar.
I'm using gradle and on the spring boot homepage are only instructions for maven.
You should use spring-boot-maven-plugin or spring-boot-gradle-plugin, depending on your preferred build system.
EDIT:
Just run ./gradlew build
I suggest to dive into this getting started guide. It clarifies a lot of stuff for beginners.
A typical Spring boot project is a Maven project or a Gradle-Project (I only know how to do it with Maven, for Gradle see [luboskrnacs answer][1]). So you just need to run the maven targetpackageand pick the jar form the (created)target` folder
use a shell, go to the project root directory (where the pom.xml file is) and type
mvn clean package
cd target
the there is the xxx.jar file.
Hello all I am trying to run a programme using Intellij. The programme runs perfectly in Eclipse and Terminal. However using IDEA it seems to ignore 2 files.
java.io.FileNotFoundException: .\data\def\items\ItemValues.txt (The system cannot find the path specified)
There are no errors normally in Intellij. I just get this error upon running it. The file is there I have checked and path is correct. Intellij just seems to be ignoring it.
Check Working directory in Run/Debug Configuration, you need to change it to $MODULE_DIR$ if you have multiple levels of maven modules.