I try to build a Spring 2.7.4 application and make a jar file. Everything is Ok until i try to start the application
java -jar demo.jar
I got the following error :
java.lang.ClassNotFoundException: org.springframework.boot.loader.JarLauncher
Acording to the Spring documentation i setup the META-INF / MANIFEST.MF
Main-Class: org.springframework.boot.loader.JarLauncher
Start-Class: com.mycompany.project.MyApplication
Intellj project scrennshot
When i look in the package org.springframework.boot there is no loader subpackage.
org.springframework.boot does not contains loader.JarLauncher class
Best regards.
Related
I've got a Spring Boot Maven project that creates an executable fat .war. I can run this .war using java -jar without any issues as all dependencies are located within the far .war.
However, I can't run the project with the Spring Boot Devtools using mvn spring-boot:run as it fails to find some dependencies at runtime and throws unhandled exceptions.
For example, we've got an indirect dependency on jaxb-runtime-2.3.1.jar which in turn has a dependency on jaxb-api.2.3.1.jar. Both .jars are present in the fat .war but if I run the project with mvn spring-boot:run it can find jaxb-runtime ok but fails to find jaxb-api with the message:
java.nio.file.NoSuchFileException: ~/.m2/repository/org/glassfish/jaxb/jaxb-runtime/2.3.1/jaxb-api-2.3.1.jar
Note, jaxb-api-2.3.1.jar is present in the maven cache at:
~/.m2/repository/javax/xml/bind/jaxb-api/2.3.1/jaxb-api-2.3.1.jar
however it seems to be looking for it in the same location as the parent jaxb-runtime-2.3.1.jar which is located at:
~/.m2/repository/org/glassfish/jaxb/jaxb-runtime/2.3.1/
There's a long list of similar exceptions that follow this pattern. It's quite a large project but here are some of the versions we're using:
Spring Boot: 2.1.9.RELEASE
spring-boot-maven-plugin: 2.1.9.RELEASE
maven-compiler-plugin: 3.8.1
spring-boot-devtools: not specified in pom
Why does spring-boot:run not locate dependencies in the same way as the maven build? How can I instruct it where to find these dependencies?
I have spring boot jar. It contains boot-inf folder with that folder it contains classes and lib folder. I need to run the certain class which is having main method. But I don't know how to run it. For normal jar we can use the below format to run the class from the jar.
java -cp "sample.jar;dependecy.jar" com.sample.ClassName
But in spring boot jar what is the format to run the class. Because it contains boot-inf folder. I am using gradle script to build the project
It should be very easy, just:
java -jar sample.jar
where sample.jar is your spring boot jar.
See https://docs.spring.io/spring-boot/docs/current/reference/html/using-boot-running-your-application.html
You can try with the distribution to run the class in a jar. Build the project to create the dist. Then you can run the class as you mentioned in the question.
java -cp "sample.jar;dependecy.jar" com.sample.ClassName
I am trying to understand the packaging of Spring Boot into "fat" jars. From what I know "fat" jars have their own special classes that load up the main class when the jar is running and also sets the classpath accordingly.
What I cannot understand is why when I use Eclipse to extract all my dependencies into a folder structure in the jar, the jar no longer runs as a correct Spring Boot application.
To repeat what I have done here just take a simple Spring Boot app and from Eclipse select the following-:
Export --> Runnable Jar --> Select Main Class --> Extract required libraries into jar.
Just run the jar from the command line as you would any jar. Spring Boot initially starts up but fails with the following message-:
2017-05-02 22:06:40.484 WARN 3468 --- [ main]
ationConfigEmbeddedWebA pplicationContext : Exception encountered
during context initialization - cancel ling refresh attempt:
org.springframework.beans.factory.BeanDefinitionStoreExcep tion:
Failed to process import candidates for configuration class
[com.main.Test Main]; nested exception is
java.lang.IllegalArgumentException: No auto configuration classes
found in META-INF/spring.factories. If you are using a custom packa
ging, make sure that file is correct.
Can I somehow edit the spring.factories file to include my classses ?
I just trying to understand how Spring actually packages the files through its Maven plugin.
I think that because it's a Spring Boot application, you need to use their plugin for building. It is because, spring Boot has its own jar loading mechanism for that (the BOOT-INF introduction in Spring Boot 1.4).
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
From documentation:
The Spring Boot Maven Plugin provides Spring Boot support in Maven, allowing you to package executable jar or war archives and run an application “in-place”.
Link to documetantion (Appendix E)
Something about spring.factories and locating auto-configuration candidates - Auto-configuration
We are using Gradle to build spring boot application.
Our application does not require commons-io. But one of the other dependencies requires commons-io. So we've not added commons-io as dependencies. gradle build worked fine.
But when we run the spring boot using "java -jar my-fat-jar.jar", it throws classNotFound Exception for a commons-io class.
My fat jar does not contain commons-io in its lib folder.
So we just added commons-io as dependencies, now everything works fine.
But we don't want to add each such dependencies. Instead is there any way to include the dependent jars of my dependencies in lib folder of my fat jar?
Please note that we are using spring boot gradle plugin.
I've got a spring boot app and I'm building a myApp.jar using the spring-boot antlib. When I jar -tf myApp.jar I see that I have a jar called lib/foo.jar. Yet when I print out System.getProperty("java.class.path") I don't see that jar file on the classpath. I also get a ClassNotFound exception from URLClassLoader when the code attempts to use this class for the first time. I'm using the JarLauncher since that's what the antlib defaults to.
Any ideas why this jar file would not be on the classpath?
You won't see a bundled JAR in System.getProperty('java.class.path'). The class path specifies where the JVM will look in the filesystem for classes you attempt to load.
Spring Boot uses fat JARs, which are loaded in a completely different way. Refer to the Spring Boot documentation.