error message "Illegal Start of Expression"?

Question

// Simple program to understand pass by reference 
import java.util.*;
public class HelloDate {
    public static void main(String args[])
    {
         class Number                     // Contains only an integer
         {
             int i;
         }
         static void f(Number k)           // <<--- Illegal start of expression ???
         {
             k.i = 22;
         } 
         Number n1 = new Number();        // New object of Number
         n1.i = 9;
         f(n1);                           //Passing an object
         System.out.println(n1.i);        // Print
      }
    }

The code is showing an error on static void f(Number k). Should I put the method void f() in a class? If yes, why is that necessary?

Right now the method `f` isn't inside your class, it's inside another method (`main`). — Jeroen Vannevel, Jul 27 '13 at 02:33
You mean other than the numerous syntax errors that make what you've posting completely not valid code? — Brian Roach, Jul 27 '13 at 02:39

score 5 · Answer 1 · answered Jul 27 '13 at 02:31

5

Methods have to be members of classes, they can only be placed in the body of a class.

answered Jul 27 '13 at 02:31

AdamSpurgin

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score 0 · Answer 2 · edited May 23 '17 at 12:15

0

It is not valid to nest methods within other methods but you can define a inner class withing a method and gain a similar effect. This previous thread has some great examples.

edited May 23 '17 at 12:15

Community

1
1

answered Jul 27 '13 at 02:37

Shafik Yaghmour

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rocketboy · Answer 3 · 2013-07-27T03:25:35.617

0

Problem is, you have a method f() directly inside another method main().

edited Jul 27 '13 at 03:25

answered Jul 27 '13 at 02:43

rocketboy

9,573
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score 0 · Answer 4 · answered Jul 27 '13 at 02:44

When you put a class in a method, it is called a local class, whose scope is only in the method.

     class Number // local class
     {
         int i;
     }

However, you cannot put a method directly in another method. You can only put a method in a class. Take your code as an example, you can put f either in HelloDate or Number.

If you put f in HelloDate, you need to put Number in HelloDate, too. Otherwise, the argument of f, Number k, will refer to java.lang.Number instead of the Number defined in main.

error message "Illegal Start of Expression"?

4 Answers4