Java run from command line — Error: Could not find or load main class / Error: cannot find symbol

If you would like to test out the simple Java program that span over multiple file.

Hello.java
MyClass.java
MyAnotherClass.java

You might see the problem like this

Error: Could not find or load main class Hello.java
Caused by: java.lang.ClassNotFoundException: Hello.java

Or if you can run it might throw

error: cannot find symbol

symbol: class MyClass
location: class Hello

Why single file run is working ?

because it compile Hello.java and store Hello.class in memory then run.

public class Hello {
  public static void main (String args[]) {
    System.out.println("hello");
  }
}

java Hello.java
// hello

Solution : Multiple file need compilation

The problem is the java does not know what to compile so you need to specify by yourself

I compile everything.

javac *.java

Then you can see the class file

Hello.java
Hello.class
MyClass.java
MyClass.class
MyAnotherClass.java
MyAnotherClass.class

Then you run where your public static void main is

java Hello.java

// Or just
java Hello

Another way is using Java package and run it with MVN or other tools but it will well suit for larger project not for some quick script or setup like this.

Hope this help and see you next time !