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How can I solve that type of issue when I compile using `javac`: " error: cannot find symbol [...]"?

For starters, I have to say that I am using IntelliJ IDEA Community Edition 2020.3.1 and running java 15.0.1 2020-10-20, also when I run my program after enabling assertions and clicking on the run button, it works as expected. That being said here is my file structure:
Here is the code in my TestRunner.java file:
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.EnumMap;
import java.util.List;
import java.util.Map;
public final class TestRunner {
private static final List<Class<?>> TESTS = List.of(CalculatorTest.class);
public static void main(String[] args) throws Exception {
List<String> passed = new ArrayList<>();
List<String> failed = new ArrayList<>();
for (Class<?> klass : TESTS) {
if(!UnitTest.class.isAssignableFrom(klass)){
throw new IllegalArgumentException("Class "+ klass + " must implement UnitTest");
}
for(Method method : klass.getDeclaredMethods()){
if(method.getAnnotation(Test.class) != null){
try{
UnitTest test = (UnitTest) klass.getConstructor().newInstance();
test.beforeEachTest();
method.invoke(test);
System.out.println(method.invoke(test));
test.afterEachTest();
passed.add(getTestName(klass, method));
}catch(Throwable throwable){
failed.add(getTestName(klass, method));
}
}
}
}
System.out.println("Passed tests: " + passed);
System.out.println("FAILED tests: " + failed);
}
private static String getTestName(Class<?> klass, Method method) {
return klass.getName() + "#" + method.getName();
}
}
Here are my issues:
When I compile my main class TestRunner.java using javac TestRunner.java, it fails to find those symbols CalculatorTest.class, UnitTest.class, Test.class, UnitTest. Here is the error message:
When I use javac *.java though, my files compile and my .class files are generated, here is a screenshot:
but when I try to run my file using java TestRunner it says: "Error could not find or load class TestRunner, here is a screenshot:
If anyone can help me solve those issues I'd would be very happy. So far, I have found no solutions when I googled about them. Thank you!

After reading many answers, I found that the solution was simple.
First compiling TestRunner.java:
javac -cp . TestRunner.java
Then running TestRunner (containing my main function):
java -cp . -ea TestRunner
It turns out I was missing on the dot "."!
Here is the final result:

How to compile several java files which depend on each other?

I have few java files. Main.java uses Picture class from Picture.java file. I want to know how to compile and run Main from command line ?
Here is Main.java:
package com.company;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
public class Main {
static Picture pic = null; // Picture class ???
public static void main(String[] args) {
long t1, t2;
String name = "bears.jpg";
pic = new Picture(name);
t1 = System.nanoTime();
pic.new_img = meanFilter(pic.img);
t2 = System.nanoTime();
pic.writeImage();
calculateTime(t1, t2);
}
and Picture.java:
...
public class Picture {
public BufferedImage img;
public BufferedImage new_img;
...

Assuming both classes are in the same directory use :
javac Picture.java Main.java
This way the dependent class (Picture.java) is compiled first before your Main.java
To run it you will need to specify the entire package structure and run it from the src directory :
java com.company.Main

You need to specify the whole package.
Try running this:
javac com.company.Picture.java com.company.Main.java

Java program not working using the command line

Short story :
When I run my java application through the Intellij it's all working.
When I run it through the command line I have some issues.
Long story:
First, I have to say that I have a 'lib' folder inside my project with all the Jars I need and I added it as a Library to the project.
When I compile it from the command line I have to specify a '-cp' to the lib folder, otherwise it doesn't load the jars. Even though it looks good, when I run my java application, I get a 'Error: Could not find or load main class awsUpdater' error
My commands :
For compiling -
javac -cp "../../../../lib/*" awsUpdater.java
For executing -
java -cp "../../../../lib/*" awsUpdater
Here's my class (besides the methods)
package AWSUpdater;
import com.amazonaws.AmazonClientException;
import com.amazonaws.AmazonServiceException;
import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.GetObjectRequest;
import com.amazonaws.services.s3.model.PutObjectRequest;
import com.amazonaws.services.s3.model.S3Object;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class awsUpdater {
public static void main(String[] args) throws IOException {
String bucketName = "bucket";
String key = "ket";
//AmazonS3 s3Client = new AmazonS3Client(new ProfileCredentialsProvider());
AmazonS3 s3Client = new AmazonS3Client(DefaultAWSCredentialsProviderChain.getInstance());
System.out.println("Downloading an object");
S3Object s3object = s3Client.getObject(new GetObjectRequest(
bucketName, key));
//Get new version of android
String newAndroidVersion = getNewAndroidVersion();
//Download current versions.json
String currentJson = displayTextInputStream(s3object.getObjectContent());
//Edit versions.json with new android version
String editedJson = editJsonWithCurrentAndroidVersion(currentJson, newAndroidVersion);
//String editedJson = editJsonDummyCheck(currentJson);
//Create new file to upload to S3
createFileWithNewJson(editedJson);
//Upload new file to S3
updateVersion(bucketName, key, "versions.json");
}
Would appreciate any help with how to compile and execute my program through the command line. thanks !

you need to add package name
java -cp "../../../../lib/*" AWSUpdater.awsUpdater

I notice that the class awsUpdater is under the package AWSUpdater, so you can not use java -cp "../../../../lib/*" awsUpdater directly.
For Example:
I create a project like this:
|-test
|-AWSUpdater
|-awsUpdater.java
Detail of the awsUpdater.java:
public class awsUpdater {
public static void main(String[] args) {
System.out.println("hello");
}
}
then(now I'm in test/AWSUpdater):
javac awsUpdater.java
java awsUpdater
Everything goes well!
If I add the class to the package, like this:
package AWSUpdater;
public class awsUpdater {
public static void main(String[] args) {
System.out.println("hello");
}
}
then(now I'm in test/AWSUpdater):
javac awsUpdater.java
java awsUpdater
here, it will got the error which is same with yours.
Now, you can go to the package's root dir. (here is test), and then:
javac AWSUpdater/awsUpdater.java
java AWSUpdater/awsUpdater
Now, you will get the correct result.

Error could not find or load main class

I want to run my class in terminal window:
D:\workEclipse2\JUnitTest\bin>java -classpath D:\JUnit\hamcrest-core-1.3.jar;D:\
JUnit\junit-4.12.jar tax.TaxCommandLineRunner
Code of my TaxCommandLineRunner class:
package tax;
import java.util.List;
import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;
public class TaxCommandLineRunner {
public static void main(String[] args) {
// TODO Auto-generated method stub
JUnitCore core = new JUnitCore();
Result result = core.run(AllTests.class);
if(result.wasSuccessful()){
System.out.println("All tax tests was successfull");
}else{
System.out.println("These tax tests was failure");
List<Failure> fails = result.getFailures();
fails.forEach(failure -> System.out.println(failure.getMessage()));
}
}
}
Compiled AllTests.class and TaxCommandLineRunner.class are located in D:\workEclipse2\JUnitTest\bin.
My jars file are located in D:\JUnit
I can't find what I'm doing wrong.

I input in terminal window:
D:\workEclipse2\JUnitTest\bin>java -classpath D:\JUnit\hamcrest-core-1.3.jar;D:\JUnit\junit-4.12.jar;. tax.TaxCommandLineRunner
I assume that point after semicolon means classpath of Windows, that is in first case I don't include my standart java\jre.

You must also add the actual directory to your classpath:
D:\workEclipse2\JUnitTest\bin>java -classpath .;D:\JUnit\hamcrest-core-1.3.jar;D:\
JUnit\junit-4.12.jar tax.TaxCommandLineRunner

not able to include package created by own in java

I have written a program that checks a data set and provides a result, i.e. if a climate condition is given for 1000 days as data set to the program it will find any deviation in the program and provide as result that major deviation.
package main;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import faster94.*;
import rules_agarwal.*;
import algo_apriori.*;
import context_apriori.*;
import itemsets.*;
public class MainTestAllAssociationRules {
public static void main(String [] arg){
ContextApriori context = new ContextApriori();
try {
context.loadFile(fileToPath("ds1.txt"));
}
catch(Exception e)
{
e.printStackTrace();
}
/*catch (IOException e) {
e.printStackTrace();
}*/
context.printContext();
double minsupp = 0.5;
AlgoApriori apriori = new AlgoApriori(context);
Itemsets patterns = apriori.runAlgorithm(minsupp);
patterns.printItemsets(context.size());
double minconf = 0.60;
AlgoAgrawalFaster94 algoAgrawal = new AlgoAgrawalFaster94(minconf);
RulesAgrawal rules = algoAgrawal.runAlgorithm(patterns);
rules.printRules(context.size());
}
public static String fileToPath(String filename) throws UnsupportedEncodingException{
URL url = MainTestAllAssociationRules.class.getResource(filename);
return java.net.URLDecoder.decode(url.getPath(),"UTF-8");
}
}
The above is the main program. There are seven files and I have created by own package, but when I run this program as a whole I cannot run it. It complains that a package is missing. i have ready provided all the seven files.
Can any one be able to run those files?

Directory tree has to reflect package tree.
So if you have a class in a package named main you class file must be in a directory named main under the working directory. So if you execute from bin/ your class must be in bin/main.
Hope this helps
Edit
The directory tre has to look like this.
bin/
-----faster94/
--------------Classes or Subpackage
-----rules_agarwal/
-------------------Classes or Subpackage
-----algo_apriori/
------------------Classes or Subpackage
-----context_apriori/
---------------------Classes or Subpackage
-----itemsets/
--------------Classes or Subpackage
-----main/
----------MainTestAllAssociationRules and other classes or subpackages
To run this use java main.MainTestAllAssociationRules in the root (bin/) directory