這是報錯

Error: Could not find or load main class .data.mfs.usercode.85.java.15010694456269ehd4t34p.HelloWorld

這是代碼：

public class HelloWorld{

? ? public static void main(String[] args) {

int a=12;

int b=24;

int sum = a + b;

System.out.println("兩數之和為："+sum);

}

}