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Jar hell for missing classes folder when running ESRestTestCase

So I'm running into a Jar hell problem when trying to run individual integration tests, using -Dtest=, that runs as a ESRestTestCase (ESTestCase). The issue here seems to be that some elasticsearch classpath validation class requires target/classes to exist. However, this project is only for testing so that requirement doesn't make sense.
This happened with Elasticsearch 7.0.0 and Java 1.8.0.251. Not sure if this is a problem with later versions.
java.lang.RuntimeException: found jar hell in test classpath
at org.elasticsearch.bootstrap.BootstrapForTesting.<clinit>(BootstrapForTesting.java:98)
at org.elasticsearch.test.ESTestCase.<clinit>(ESTestCase.java:229)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at com.carrotsearch.randomizedtesting.RandomizedRunner$2.run(RandomizedRunner.java:623)
Caused by: java.nio.file.NoSuchFileException: <MY PROJECT FOLDER PATH HERE>/target/classes
at sun.nio.fs.UnixException.translateToIOException(UnixException.java:86)
at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102)
at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107)
at sun.nio.fs.UnixFileAttributeViews$Basic.readAttributes(UnixFileAttributeViews.java:55)
at sun.nio.fs.UnixFileSystemProvider.readAttributes(UnixFileSystemProvider.java:144)
at java.nio.file.Files.readAttributes(Files.java:1737)
at java.nio.file.FileTreeWalker.getAttributes(FileTreeWalker.java:219)
at java.nio.file.FileTreeWalker.visit(FileTreeWalker.java:276)
at java.nio.file.FileTreeWalker.walk(FileTreeWalker.java:322)
at java.nio.file.Files.walkFileTree(Files.java:2662)
at java.nio.file.Files.walkFileTree(Files.java:2742)
at org.elasticsearch.bootstrap.JarHell.checkJarHell(JarHell.java:199)
at org.elasticsearch.bootstrap.JarHell.checkJarHell(JarHell.java:86)
at org.elasticsearch.bootstrap.BootstrapForTesting.<clinit>(BootstrapForTesting.java:96)
... 4 more

At first I tried various methods for making sure the classes folder was still created. I ran into new problems that seemed fixed in later versions so I upgraded to Elasticsearch 7.6.2 (And lucene 8.4.0). Upgrading seemed to remove the need for the folder to exist but triggered other issues (similar to this). I worked around such issues with -Dtests.security.manager=false. Then I got thread leak issues which I "solved" by setting #ThreadLeakScope(ThreadLeakScope.Scope.NONE) on the test class.
Then finally it seemed to work when running maven in command line for individual tests. But when trying to run the maven task with debugger in Intellij the debugger does not seem to attach.
So I try to run it as JUnit templated test in Intellij. Here I get jar hell when running it but it works to debug. The jar hell was later solved by setting idea.no.launcher=true in idea.properties.
Alright, good enough for now. These workarounds are far from ideal but it works for my current purposes. A lot of things will change before moving into mainline anyway. And maybe this will help someone else. Hopefully I can post a better solution later.

Adding new aggregate function in Presto fails

I am trying to build custom aggregate functions for presto. I have created a FAT Jar and deployed the jar into the plugin directory. When I restart presto, it is always giving me this error :
java.lang.AbstractMethodError
at com.facebook.presto.server.PluginManager.installPlugin(PluginManager.java:183)
at com.facebook.presto.server.PluginManager.loadPlugin(PluginManager.java:175)
at com.facebook.presto.server.PluginManager.loadPlugin(PluginManager.java:158)
Unfortunately, I do not see any verbose error message which will give me a clue on what is actually missing here. I used presto-ml plugin as an example and implemented getFunctions() in plugin implementation. Is there a way to figure out what is missing?
I did check the source code of PLuginManager.java. I am just looking for a way to debug this in a better way.

AWS Java SDK Error - java.lang.NoSuchMethodError

I've seen this type of error over here for exceptions that are thrown by various classes, though I haven't found the right solution for mine just yet.
I'm trying to get AWS Java SDK work locally so I can write a test application that reads data from a Kinesis stream.
Problem is, when I run the init() static method I encounter the following error:
Exception in thread "main" java.lang.NoSuchMethodError:
org.apache.http.impl.conn.DefaultClientConnectionOperator.<init>
(Lorg/apache/http/conn/scheme/SchemeRegistry;Lorg/apache/http/conn/DnsResolver;)V
Now, this is not the first error I've been thrown. I've been thrown four or five exceptions prior to this one, and the solution to all of them was just importing some jar's into the project. e.g.:
apache-httpcomponents-httpclient.jar
com.fasterxml.jackson.databind.jar
commons-codec-1.9.jar / commons-codec-1.9-javadoc.jar / commons-codec-1.9-sources.jar
httpclient-4.2.jar
httpcore-4.0.1.jar
I've seen in other threads around here that it could be the version of the httpcore library, however I imported the latest one.
Any ideas how I can resolve this? I'm thinking about starting over, as my project seems to be a heap of imports I'm not sure I'll actually utilize. Furthermore, I can't debug the binary imports of the AWS SDK (or can't I?).
Cheers.

Problem solved, I gradually added the missing libraries to the project and when the apache httpclient jar should be version 4.0 or later, and without any previous version to contradict.
I imported httpclient-4.2.jar and it worked.
Other than that, I just solved the exception that followed by importing joda-time-2.4.jar and it's all up and running.

NO java.lang.NoClassDefFoundError error in Eclipse

I have a project in eclipse which was working fine untile a few minutes ago. I added a JDBC driver ad tried to run it, now even previous runnable file are giving me
Exception in thread "main" java.lang.NoClassDefFoundError: sample
Does anyone have any idea why it is happening does it have anything to do with the jar?
I have even removed the jar.

Try following, one by one
If you are using libraries, check whether everything is included to the project properly.
Rebuild the project
'worked few minutes ago' means it used to work. Did you add any new code? Then the error is there, check whether those codes call other classes, and whether they are available
Restart IDE
Once I used the following to solve the same issue
http://javarevisited.blogspot.com/2011/06/noclassdeffounderror-exception-in.html
If all above failed, that may be due to crash in JVM. I have experienced that as well.

Eclipse ClassNotFoundException

Everything works fined, but suddenly eclipse stopped execute and junit tests or even main method, when i run them using run as - > Java application, run as -> junit test
It simply throws error
Caused by: java.lang.ClassNotFoundException: package.ClassName
whene ClassName - is class from where i trying to run method main.
It affect only one of my projects ... Different workspaces works fine, other project in same workspace works fine as well.
I'm sure if i recreate current project, error will gone. But the adjustments of this project in eclipse is really hard, so i want to avoid it.
Any clue?

The ClassName is not in the Class Path, if you start from console you should use -cp parameter , if from eclipse, please add ClassName to the sources of current(start) project.

Thanks to adarshr, I was able to look at the Problems window and determine that the build was failing because it could not find a class I had written.
I had used the MS TFS plugin to create a "shelveset" and it was supposed to have removed my pending changes in the process. However, this integration with the TFS snapin and Eclipse is obviously not well implemented, since the Eclipse project still thought the file existed and was complaining that it could not be compiled.
I went and manually deleted those "files" or "non-existing files" from the Eclipse project (that I thought I had removed with the shelveset action) and the problem was solved.
Also....
Another annoying things is that the Tomcat error I was getting by trying to debug within Eclipse was like this:
SEVERE: Error configuring application listener of class
com.CompanyName.ProjectName.servlet.StartupConfigListener
java.lang.ClassNotFoundException:
com.CompanyName.ProjectName.servlet.StartupConfigListener at
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1643)
In reality, there was no problem at all with StartupConfigListener.java!! The build failed due to the OTHER problems I mentioned above, and therefore I guess this was the first class it attempted to load and failed.... because the entire project hadn't been able to compile perhaps?
(Here's to hoping my next project is using Visual Studio instead of Eclipse!)

Ok, I finally figured it out. The problem was with installed JRE in eclipse setting. I was playing around with this setting and changed installed JRE to JDK, and for some reason it broke the eclipse project.

You can also try going back to the basics. Check your command line and VM args. I've had this situation where a VM arg I was passing in was a path to a file that had a space in the path, and I had forgotten to include the full path in quotes. So e.g., if my arg looked something like
-DFILE=C:\Documents and Settings\myfile
...I'd get a java.lang.NoClassDefFoundError caused by a java.lang.ClassNotFoundException.