May I ask about the "java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver".
Per Java document, the PATH and CLASSPATH shall be configured in the Windows 10 environment variables .

Below are information regarding the system/database version and what I did.

The Java version is as below.
C:\>java -version
java version "1.8.0_281"
Java(TM) SE Runtime Environment (build 1.8.0_281-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.281-b09, mixed mode)

The JAVA_HOME is
C:\Program Files\Java\jre\1.8.0_281

The CLASSPATH has
C:\Program Files\Java\jdk\1.8.0_281
C:\Program Files\Java\jdk\1.8.0_281\bin
C:\Program Files\Java\jre\1.8.0_281
C:\Program Files\Java\jre\1.8.0_281\bin
C:\Oracle_RDBS_installation\product\12.2.0\client_1\bin
C:\Oracle_RDBS_installation\product\12.2.0\dbhome_1\bin

The compilation of Java program was successful by using "javac". But the class not found error message was returned during the run time.

I have no problem accessing the Oracle database from Sql*Plus at all. I created two users, created a simple table for the sake of testing.
Everything worked fine. I have no problem with the listener and the TNSNAES.ORA.

Below is the information about database:

SQL*Plus: Release 12.2.0.1.0 Production on Wed Apr 21 09:08:05 2021

Copyright (c) 1982, 2016, Oracle. All rights reserved.

Enter user-name: c##_chiara
Enter password:
Last Successful login time: Sat Apr 17 2021 09:46:21 -04:00

Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production


Below is the Java code:
<Begin of the Java Code>



import java.sql.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;


public class Thirdj3 {
public static void main(String[] args){
System.out.println("Beginning of the Thirdj3 program.");


try{
//step1 load the driver class
Class.forName("oracle.jdbc.driver.OracleDriver");

//step2 create the connection object
Connection con=DriverManager.getConnection(
"jdbc:oracle:thin:@DESKTOP-JBRID90.home:1521:orcl","c##_chiara","chiara");

//step3 create the statement object
Statement stmt=con.createStatement();

//step4 execute query
//*ResultSet rs=stmt.executeQuery("select * from emp");
//*while(rs.next())
//*System.out.println(rs.getInt(1)+" "+rs.getString(2)+" "+rs.getString(3));

//step5 close the connection object
con.close();

}
catch(Exception e){ System.out.println(e);}



}//End of main
}//End of Thirdj3 Class


<end of the java code>

set CLASSPATH=%CLASSPATH%;c:\oracle\sqldeveloper\jdbc\lib\ojdbc8.jar