在Java中博士

Question

import java.util.Scanner; 
    public class Question_11 { 

     public void main(String[] args) { 


     double RATE = 35.75; 
     double Wages; 
     double Hours; 

     Scanner keyboard = new Scanner(System.in); 


     System.out.print("Please enter the number of hours worked: "); 
     Hours = keyboard.nextDouble(); 

     //calculate wages 
     Wages = Hours * RATE; 

     System.out.println("The calculated wages = " + Wages); 

    } 

} 

空指針異常這是我的代碼，我不斷收到此錯誤：

java.lang.NullPointerException 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
at java.lang.reflect.Method.invoke(Method.java:597) 
at edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:272) 

它編譯，但不會運行。

預先感謝您！

Answer 1

這是Dr. Java的令人討厭的不倫不類的棧跟蹤，當VM未找到main方法時發生。

即：在static關鍵字添加到主方法使應用程序具有

public static void main(String[] args) {