Trouble running java app from cmd

Question

I have two files, app.java and test.java They both reside in the same package, and they compile just fine with "javac app.java test.java" Two class files are then created. However, when I go to run them with the command "java app" because app has the main method, I get "Error: Could not find or load main class app"

app.java:

package working_directory;

public class app {

public app() {

}

public static void main(String [] args) {
    test testing = new test();
    System.out.println(testing.calculate(60));
}
}

This Is the test.java

package working_directory;

public class test {

public test() {

}

public int calculate(int x) {
    return (int) x * x * x;
}
}

Answer 1

Make sure to choose the right path for compilation and running code:

D:\
 +--Folder(start cmd here)
       +---working_directory
                          +----app.java
                          +----test.java

How to compile

D:\Folder\>javac working_directory\*.java

How to run

D:\Folder\>java working_directory.app