When I try doing the serialization examples from Ruminations of a Programmer's "JSON Serialization for Scala Objects" article I run into the error:
Exception in thread "main" java.lang.NoClassDefFoundError: scala/util/parsing/syntax/Tokens.
I have found that it happens when trying to deserialize. I was just wondering if there was a simple fix. I would really like not having to redo my whole project and downloading all my jars again.
This mainly occurs when the scala library is not present in your source path.
just check that it is present in build path.
If you are using eclipse the plugin doesnt work properly some times.Just make a new folder in your project and paste scala library into it and give it to build path.
Related
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 spent the last 1,5 hour trying to make this simple tutorial work in IntelliJ IDEA, as you can see in this video.
When trying to run the code, I get the error:
/[...] -Dfile.encoding=UTF-8 src.HelloKt
Error: Could not find or load main class src.HelloKt
Caused by: java.lang.ClassNotFoundException: src.HelloKt
I have tried setting up SDK, invalidating cache, removing .idea and .gradle, rebuilding project, deleting the profile and adding it again. I tried those actions in different orders.
Here's a screenshot of the project:
It also complains Kotlin is not configured, but I have already configured it.
Here's the run configuration:
Here are the project settings:
Your Hello.kt file needs to be somewhere inside the src/main folder, probably in src/main/kotlin. This is different from the tutorial, because your project is using Gradle, and the one in the tutorial isn't. I think this is because newer versions of IntelliJ use Gradle by default for new projects, which wasn't the case when the tutorial was written.
The use of src/main/kotlin and src/test/kotlin as source code directories is a convention in Gradle (and Maven). When importing a Gradle project into IntelliJ, main becomes a module, and kotlin becomes a source folder within that module. The same goes for test. In your screenshots, the bold text and blue icons on main and test confirm that's how your project is set up. Files outside of those folders aren't treated as source files, which explains why your Hello.kt file isn't being compiled or recognised correctly.
It's likely that the default behaviour of IntelliJ when creating a new project has changed since this tutorial was written. In the tutorial, they select "Kotlin" as the project type and this creates a project that doesn't use Gradle. As a result, the project doesn't use the src/main/kotlin directory structure.
I can see from your video that you selected the same option, but on the next screen, IntelliJ still automatically selected Gradle as the build system for the new project. To match the project structure used in the tutorial, I think you would need to select "IntelliJ" as the build system.
This is very close to what I'm trying to accomplish. How to compile and run kotlin program in command line with external java library
I really want to learn how to compile and run simple code that includes libraries but am getting a bit lost when it comes to including classpaths.
I’m currently trying to compile and run
import kotlinx.serialization.*
import kotlinx.serialization.json.*
#Serializable
data class Project(val name: String, val language: String)
fun main() {
// Serializing objects
val data = Project("kotlinx.serialization", "Kotlin")
val string = Json.encodeToString(data)
println(string) // {"name":"kotlinx.serialization","language":"Kotlin"}
// Deserializing back into objects
val obj = Json.decodeFromString<Project>(string)
println(obj) // Project(name=kotlinx.serialization, language=Kotlin)
}
using
kotlinc -cp "C:\PROGRA~1\Kotlin\lib\kotlinx-serialization-runtime-1.0-M1-1.4.0-rc.jar" main.kt
to compile with this compiler
https://blog.jetbrains.com/kotlin/2020/07/kotlin-1-4-rc-released/
allowed lib at bottom of the article
that's where kotlinx-serialization-runtime-1.0-M1-1.4.0-rc.jar is coming from. I chose this runtime jar because when I use the new kotlin 4.0.21 compiler it requires the kotlin-serialization-runtime-1.0.1.jar which you need to build yourself but when I download the source and run gradle build it doesn't seem to get generated (separate problem but would love to know how to build the runtime jar myself)
when I try and run I get
Exception in thread "main" java.lang.NoClassDefFoundError: kotlinx/serialization/json/Json
at MainKt.main(main.kt:12)
at MainKt.main(main.kt)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.jetbrains.kotlin.runner.AbstractRunner.run(runners.kt:64)
at org.jetbrains.kotlin.runner.Main.run(Main.kt:149)
at org.jetbrains.kotlin.runner.Main.main(Main.kt:159)
Caused by: java.lang.ClassNotFoundException: kotlinx.serialization.json.Json
at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:435)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:589)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
... 9 more
I know I need to include a classpath when I run
kotlin MainKt
but have tried everything with no success
I've tried many different combinations of things including
compiling with and without
-Xplugin="C:\PROGRA~1\Kotlin\lib\kotlinx-serialization-compiler-plugin.jar doesn't seem to make a difference so I left it off.
I have tried compiling to both a java .jar as well as a kotlin .class file both seem to need classpath information at runtime. I would rather compile to a kotlin .class and keep java out of this until I really need it. This way I can learn what java is really doing in my application.
I guess what I really want to know is how one can determine what is required at runtime for an executable to run. I found this site which helps show dependencies but is for older versions of kotlin https://kotlin.binarydoc.org/org.jetbrains.kotlin/kotlin-compiler-dist/1.3.71/package?package=kotlinx.serialization
I’ve also been peaking into the .class files using https://github.com/google/android-classyshark
and
https://github.com/borisf/classyshark-bytecode-viewer
but still when people tell others, on StackOverflow, what classpath they need to use to solve their problem it seems like magic. Can someone out there teach me how to fish without gradle?
p.s. If anyone has any good resources on learning the internals of how gradle is building the project. I've looked here a bit https://docs.gradle.org/current/userguide/userguide.pdf but didn’t seem to help. maybe I missed something. Also, this page https://kotlinlang.org/docs/reference/serialization.html#example-json-serialization seems to have what I need but can't seem to transfer that to what the command line needs.
dependencies {
implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.0.1")
}
what does this mean? I think this is referring to this https://github.com/Kotlin/kotlinx.serialization
but then how can I build what I need from this repo and use it to allow my application to know where its runtime dependencies are? ugh. I really wanted to figure all this out myself, but I must kneel to the internet gods for this one. Sorry, my post is a mess. I love to learn.
It took some time but I was able to build and run the serialization sample found at https://github.com/Kotlin/kotlinx.serialization on the command line using the current kotlinc compiler and the kotlinx.serializtion.1.0.1 library.
Here are the direct links to the compilers and libs
kotlinc and kotlinc-native v1.4.20
https://github.com/JetBrains/kotlin/releases/tag/v1.4.20
Kotlinx.serialization v1.0.1
https://github.com/Kotlin/kotlinx.serialization/releases/tag/v1.0.1
These both can also be found in the 1.4.20 releases blog post under the section titled How To Update:
https://blog.jetbrains.com/kotlin/2020/11/kotlin-1-4-20-released/
Setting Up Katlin’s .jar Libraries
After updating my path to point to the new compilers I still needed to build the serialization libs. This was as simple as running gradle build in the root directory of the unzipped kotlinx-serialization-1.0.1 folder. Make sure to set your JAVA-HOME system variable before you do this or it won’t work.
Once it's built you need to grab both the kotlinx-serialization-json-jvm-SNAPSHOT-1.0.1.jar and the kotlinx-serialization-core-jvm-SNAPSHOT-1.0.1.jar files and move them into the project directory. This definitely confused me because I had found a runtime lib for kotlinx serialization on the MVN repository site that was one jar file, but I wasn't seeing it after building the 1.0.1 libraries. Once I extracted the 1.0.1 runtime jar I found online, by renaming the .jar to .zip, it became apparent that it consisted of both the contents of the core and json jars. Don’t use the kotlinx-serialization-1.0.1-SNAPSHOT.jar. This jar only contains a blank MANIFEST.ms file. You can find the kotlinx-serialization-core-jvm-1.0.1-SNAPSHOT.jar in the kotlinx.serialization-1.0.1\core\build\libs folder and the kotlinx-serialization-json-jvm-1.0.1-SNAPSHOT.jar in the kotlinx.serialization-1.0.1\formats\json\build\libs folder. anyways.
Compiling Your .jar Library
once you have the jars in your project folder you can build your project
I included my cleanbuildandrun.sh shell script down below for easy reference.
My first attempt 1) was to try and build the project without compiling it to a .jar library file. This was a complete failure. I got it to compile but running the project proved much harder. I was unable to tell kotlin where the libraries were at runtime. I tried so many different things Including trying to point it to a manifest file I created but nothing seemed to work. It seems you need to build an executable jar in order to make this work. which brings me to my second try 2). This is where I found more success.
Attempt 2)
First you need to include the kotlinx-serialization-compiler-plugin.jar using the "-Xplugin" compiler flag. My understanding is that plugins are used to define annotations to the compiler like #Serializable. You can find this jar file in the lib folder inside the compiler you just downloaded. I copied this into my projects /lib folder next to the other jar files to make things self-contained and portable.
Next you need to tell the compiler where to find the library classes you want to access using the "-classpath" or "-cp" compiler flag.
Make sure to include kotlin runtime libraries using the "-include-runtime" compiler flag. This will bundle the kotlin standard class libraries within your jar so you don’t need to point at them during runtime.
Last direct the compiler to build a jar file by providing the -d compiler flag with the name and extension of your soon to be .jar file. That’s it, your off compiling.
Example Shell Script:
#!/bin/bash
sh clean.sh
case $1 in
1) # Comming Soon
kotlinc -verbose -Xplugin="lib\kotlinx-serialization-compiler-plugin.jar" \
-cp "lib\kotlinx-serialization-json-jvm-1.0.1.jar;lib\kotlinx-serialization-core-jvm-1.0.1.jar" \
main.kt
;;
2) # Working
kotlinc main.kt -Xplugin="lib\kotlinx-serialization-compiler-plugin.jar" \
-cp "lib\kotlinx-serialization-json-jvm-1.0.1.jar;lib\kotlinx-serialization-core-jvm-1.0.1.jar" \
-include-runtime -d main.jar
jar ufm Main.jar ManifestAdditions.txt lib
kotlin main.jar
;;
3) # Comming Soon
kotlinc-native main.kt -verbose -Xplugin="lib\kotlinx-serialization-compiler-plugin.jar" \
-cp "lib\kotlinx-serialization-json-jvm-1.0.1.jar;lib\kotlinx-serialization-core-jvm-1.0.1.jar" \
-manifest ManifestAddition.txt -o main
;;
esac
Running your .jar Library
By default, when you compiled the jar it created a MANIFEST.ms file that it uses to tell your jar library where the entry point is. which would be enough if we weren’t using additional libraries in our application. So next we need to add those libraries to the jar file we compiled while at the same time updating its MANIFEST.ms file to tell it where those libraries are within that jar file. We can use the cli tool jar to accomplish this. With the command:
jar ufm Main.jar ManifestAdditions.txt lib
we are able to update the current jar file.
u - tells jar we want to update an existing jar file
f - indicates that we are providing the jar file we want to update on the cmd line
m - indicates that we will be providing the manifest file
The Manifest .txt file should look like this:
Main-Class: MainKt
Class-Path: lib\kotlinx-serialization-core-jvm-1.0.1.jar lib\kotlinx-serialization-json-jvm-1.0.1.jar
Make sure to add a new line at the end of the file or it won’t parse the Class-Path.
That’s it. Now we have an executable jar file that we can use to run our serialization code on the command line:
kotlin main.jar
should output:
{"name":"kotlinx.serialization","language":"Kotlin"}
Project(name=kotlinx.serialization, language=Kotlin)
Post Mark
I would really like to turn this answer into a blog post that explains how to use the kotlin compiler, with libraries, on the command line. The information is out there but it seems to be scattered. I would like to include how to compile and run without using jar files, if that’s even possible, as well as how to compile and run using the native compiler. If anyone can help fill in these gaps it would be much appreciated. I think this information could help others learn how to set up simple test environments so they can better understand the functionality of these libs without having to set up a build script. This will be my first attempt at creating a tutorial type blog post so any information would really help.
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.
If I run the application in server, which is working fine, but If i run application in anypoint studio doesn't run. Here is the error message for loading oracle driver.
error message:
2015-02-04 11:18:34 WARN DriverManagerDataSource:107 - Could not load driverClass oracle.jdbc.OracleDriver
java.lang.ClassNotFoundException: oracle.jdbc.OracleDriver
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
I have placed all jdbc and other jars under studio->project->properties->libraries.
This is caused by the Studio's classloading policies. The workaround is to copy the JDBC Driver .jar to ${studio.home}/plugins/org.mule.tooling.server.${mule.version}.ee_${mule.version}.${release.date}/mule/lib/user
Hi there actually that's kind of a hack :P though it works.
The more proper way to deal with this is, when coding your application (that's why one should use Mule Studio), to place the jars like drivers in a particular folder, like a /lib in the root of you project.
Then add these jars to the classpath.
I know what you did is the way it should be done when running on Mule stand alone in order to share such jars but try this one if you can ;)
I was also facing the same problem. As the application runtime fails to locate the jdbc driver jar in classpath So It is unable to load the same.
the simple and easiest way to handle this error is just put your lib folder containing the ojdbc jar file inside the app resource (src/main/app) of the project. During the building of project it will automatically be place in classpath.
I have tried the same approach and It works for me.
Hope this helps.
The way I fixed the problem was removing the .classpath / .project files from my project root folder. I re-imported the project and then I saw a bin folder created. I removed this bin folder then right-click on the project -> Refresh and then Run As -> Mule Application.