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Get NoClassDefFound Error in Apache Maven 3.8.6 (JDK-19+Gson2.10)

I am new to java and maven. I am learning and trying to make a system to help me build up JSON data by GOOGLE's gson and maven. This is my using command order:
mvn -f my-app\pom xml clean compile
mvn -f my-app\pom xml install
cd my-app\target
java -jar my-app-1.0.jar
After I run it it show me this error.
in GSONExample.java Line 13:
Gson gson = new Gson();
The following is my using software/IDE version.
Source Editor: VS Code
JDK: JDK-19
apache-maven: 3.8.6
Gson: 2.10 (https://github.com/google/gson/releases)
I have already gone through other websites and StackOverflow to find solutions.
GSON is not being imported into the maven project Changed scope role and still crash
error even though it is defined in my classpath /WEB-INF/lib can't find in my situation
Now below a part of my pom.xml
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.10</version>
</dependency>
I also had try to import it(Gson) to local and try to fix it out.
mvn install:install-file -Dfile=C:\gson-2.10.jar -DgroupId=com.myself.gson -DartifactId=example-gson -Dversion=2.10 -f my-app\pom.xml
After I use the command, I changed pom.xml as follow. It can compile and install. But still show me "NoClassDefFound"
<dependency>
<groupId>com.myself.gson</groupId>
<artifactId>example-gson</artifactId>
<version>2.10</version>
</dependency>
May anyone provide any solution to this? Thanks in advance.
I had tried
changed scope to provided in pom.xml
put Gson in src\main\resources\lib and change pom.xml
Local gson-2.10.jar and change pom.xml
put gson-2.10.jar in C:\Program Files\apache-maven-3.8.6\lib

The problem is this command:
java -jar my-app-1.0.jar
Most likely your current Maven pom.xml creates a JAR file which contains only the classes of your project, but not the classes of dependencies, such as Gson. This is also not specific to Gson but applies to any dependencies you are trying to use. You can either:
use java -cp and specify the path to your JAR as well as the paths to all the JARs of dependencies you are using, for example java -cp gson-2.10.jar;my-app-1.0.jar com.mycompany.app.GSONExample
configure Maven to build a "JAR with dependencies", see this question whose answers describe multiple ways of how this can be achieved

error: package org.slf4j does not exist

I am attempting to create a program in Java using Netbeans. I am attempting to use org.slf4j. I think I have placed the sufficient amount of slf4j jar files in my CLASS PATH. I have placed slf4j-api, slf4j-jcl, slf4j-jdk14, slf4j-nop and slf4j-simple in my class path.
My question is: Am i placing the wrong jar files in my class path, the Zip file for the slf4j folder included a large amount of jar files. Why are there so many executable jar files included for SLF4J.
Ultimately, the program needs to compare 2 pdf files at a time and spit out an error message if the files are different. Would anyone know if there is anything out there that I can include so I don't have to deal with this SLF4J package.
Below is where I am attempting to run the package.
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

Set Dependencies as follows.
In Maven
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>version number</version>
</dependency>
In Gradle
dependencies {
compile group: 'org.slf4j', name: 'slf4j-api', version: 'version number'
}

In Gradle add the following dependencies:
implementation 'org.slf4j:slf4j-api:1.7.28'
implementation 'org.slf4j:slf4j-simple:1.7.28'
The last one dependency needs to be added to Resolve "Failed to load class org.slf4j.impl.StaticLoggerBinder"

In build.gladle ( the second one ) look at dependencies and add this line:
dependencies {
...
implementation 'org.apache.directory.studio:org.slf4j.api:1.7.2'
}

java.lang.ClassNotFoundException: org.apache.hadoop.conf.Configuration

I keep getting this error.I've included the hadoop commons and the core libs in the classpath but still i keep getting this error.Help would be highly appreciated

Here's how to troubleshoot: Look inside the jar that you're executing to see if that class file is actually there:
jar tvf target/my-jar-with-dependencies.jar | grep hadoop/conf/Configuration.class
If it's not, you need to add it to your classpath or change the way your jar is packaged.
Are you using Maven or some similar build tool? You may have a dependency with a 'scope', which means that it will only be compiled into your jar in certain circumstances.
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>${hadoop.version}</version>
<scope>provided</scope>
</dependency>
In this example, the scope tag tells Maven that you're using this dependency for building, but it indicates that the dependency will be provided during runtime, so you'll either need to remove this tag or add the hadoop jar using -cp=/path/to/jar.jar during runtime. Another example of a scope like this is 'test', which indicates that the jar is only needed in the path during unit tests.

make sure the classpath in your jar. You can check it like mark said;
jar tvf target/my-jar-with-dependencies.jar | grep hadoop/conf/Configuration.class

add dependency to hadoop-core.

import org.apache.commons.httpclient.*

I use a code that imports the following package:
import org.apache.commons.httpclient.*;
I use eclipse. I went to http://hc.apache.org/downloads.cgi & I downloaded the Jar files, I added them to my project. Still eclipse making an error for this.
Exception in thread "main" java.lang.Error: Unresolved compilation
problems: HttpClient cannot be resolved to a type
What is the problem?

If you are using the latest (4.x) version of these modules, they have been refactored a lot.
For example, the package name is now org.apache.http.client.
Old sample code will have to be modified.
Look at the Javadocs and the Quickstart for the new project.
The (discouraged) alternative would be to get the old (3.x) version.

I would recommend using Maven for managing your 3rd party dependencies. It takes care of jar files & all related dependencies.
The maven dependency for httpclient is:
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.2.1</version>
<scope>compile</scope>
</dependency>

Signer information does not match

I'm receiving the following error on log file.
(java.lang.SecurityException: class
"com.adventnet.snmp.snmp2.SecurityModelTable"'s signer information
does not match signer information of other classes in the same
package thrown
The thing is when I run the below command, it says the jar is verified.
/usr/jdk/instances/jdk1.5.0/bin/jarsigner -verify -verbose Jarfile.jar
If the jar file is verified then how can this problem occur?

It means that you have two or more classes in the same package with different signature data. Usually that means the classes come from different JARs, one of which is signed and the other is unsigned.

Check the pom dependency tree for same packages of different versions.
I had this issue with itext-2.1.7 including old bouncycastle's bcpkix that was included in a later version elsewhere.
Use this pattern:
<dependency>
package X
<exclusions>
<exclusion>
old package Y
</exclusion>
</exclusions>
</dependency>
<dependency>
latest package Y
</dependency>
Update: To check the dependency tree details of package_Y you can use mvn dependency:tree -Dverbose -Dincludes=package_Y. For more info check maven documentation on resolving dependency tree problems. Also Eclipse has quite a nice dependency tree viewer.

I encountered this exception while running a Scala/Spark project in Eclipse (Mars) on Windows and it prevented me from debugging and running the project in the IDE. The project used a Maven pom.xml file. It took a while to resolve, so I'm posting detailed steps here to help others:
Go to the folder where your project pom.xml file is
Run the command: mvn dependency:tree -Dverbose >Depends.Txt
Make sure you don't have a Depends.Txt or it will be overwritten!
Search in the Depends.Txt file for the unsigned class that the Eclipse IDE is complaining about. In my case, it was javax.servlet.
You may find it in a section that looks like this:
+- org.apache.hadoop:hadoop-mapreduce-client-core:jar:2.6.0:provided
+- javax.servlet:servlet-api:jar:2.5:provided
The Maven group ID that you want to exclude the duplicate class from in the above is: hadoop-mapreduce-client-core
Add an exclusions section listing the groupid of the exclusion in the pom.xml after the offending package. In my case, this was the groupid javax.servlet.
Note that you can't resolve this issue by reordering the Java build path as some have posted for a similar problem.

I encountered this issue in a Spring boot application. My issue was that I had JUnit on the build path which has Org.hamcrest.Matchers.* and Hamcrest which was resident in the library of the Spring framework in my pom.xml for the Eclipse repository. What I did was remove JUnit from my build path and included it only in my pom.xml. My application depended on Maven for JUnit and the *Matchers, so somehow you have two jars for one need, maybe as a library and as a configuration file.

In my program, I have loaded two versions of the same package. One is boprov-jdk15-140.jar, the other is bcprov-jdk15-151.jar. The two are conflicted.
In the JAR package's MANIFEST.MF file, it has the following digest:
Name: org/bouncycastle/crypto/digests/SM3Digest.class
SHA1-Digest: xxxxxxxx
The two JAR files have different SHA1-Digest info.

In my case I had:
Caused by: java.lang.SecurityException: class "org.bouncycastle.util.Strings"'s signer information does not match signer information of other classes in the same package
It was a project with a lot of dependencies and the mvn dependency:tree information did not really helped me.
Here is how I solved my issue:
I did a search "Find in files" using notepad++ on all the M2_REPO
I found a project which redefined "Strings" class in a package exactly identical to "org.bouncycastle.util.Strings" which should originate from the "org.bouncycastle:bcprov-jdk15on" dependency.
Once found, I moved all of these problematic classes in a new package and updated this project version.
Finally I updated the pom of the project which caused me trouble in the first place to use my dependency that uses the new package name.
Problem solved.

I had the following error:
java.lang.SecurityException: class “org.bouncycastle.asn1.ASN1ObjectIdentifier”‘s signer information does not match signer information of other classes in the same package
I was facing this exception when I was trying to make a PDF password protected.
I added the below jars to resolve the problem.
◾itextpdf-5.2.1.jar
◾bcmail-jdk16-1.46.jar
◾bcprov-jdk16-1.46.jar
◾bctsp-jdk16-1.46.jar