how to use testng directly from bash?

I'm not seeing why java cannot find App as it's explicitly added to the classpath:

nicholas@mordor:~$ 
nicholas@mordor:~$ java -cp /usr/share/maven-repo/org/testng/testng/debian/testng-debian.jar:/home/nicholas/NetbeansProjects/testng_gradle/src/main/java/testng_gradle/App /home/nicholas/NetBeansProjects/testng_gradle/app/src/test/java/testng_gradle/AppTest.java /home/Nicholas/NetbeansProjects/testng_gradle/test.xml
/home/nicholas/NetBeansProjects/testng_gradle/app/src/test/java/testng_gradle/AppTest.java:11: error: cannot find symbol
        App classUnderTest = new App();
        ^
  symbol:   class App
  location: class AppTest
/home/nicholas/NetBeansProjects/testng_gradle/app/src/test/java/testng_gradle/AppTest.java:11: error: cannot find symbol
        App classUnderTest = new App();
                                 ^
  symbol:   class App
  location: class AppTest
2 errors
error: compilation failed
nicholas@mordor:~$ 
nicholas@mordor:~$ tree NetBeansProjects/testng_gradle/
NetBeansProjects/testng_gradle/
├── app
│   ├── build.0
│   ├── build.gradle
│   ├── src
│   │   ├── main
│   │   │   ├── java
│   │   │   │   └── testng_gradle
│   │   │   │       └── App.java
│   │   │   └── resources
│   │   └── test
│   │       ├── java
│   │       │   └── testng_gradle
│   │       │       └── AppTest.java
│   │       └── resources
│   └── test.xml
├── gradle
│   └── wrapper
│       ├── gradle-wrapper.jar
│       └── gradle-wrapper.properties
├── gradlew
├── gradlew.bat
├── settings.gradle
└── test.xml

12 directories, 11 files
nicholas@mordor:~$ 
nicholas@mordor:~$ uname -a
Linux mordor 5.11.0-25-generic #27-Ubuntu SMP Fri Jul 9 23:06:29 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
nicholas@mordor:~$ 

Ideally, would like to use bash as:

java -Dtestng.test.classpath="c:/build;c:/java/classes;" org.testng.TestNG testng.xml

but in using linux perhaps have gotten the command mixed up.

This is about the simplest testng example possible.