MethodLocalClass Question

[liqiang yang]

public class Test1 {
public static void main(String[] args) {
final int a=1; // Line 1
final int b; // Line 2
b=10; // Line 3
class MethodLocalClass {
System.out.println(a); //Line 4
}
}
}

Why it fails to compile on Line 4?
Method Local Class can access its enclosing method's final var, right?
Anybody can fix it? Thanks.

[marc weber]

Originally posted by liqiang yang:

...class MethodLocalClass {
    System.out.println(a); //Line 4         
}...

A nested class is just like any other class in that statements need to be inside methods.

[Karl Prenton]

surround with braces i.e. an initialization block (non-static) :

{
System.out.println(a); //Line 4
}

[liqiang yang]

Thanks Frank, Can you explain a little bit, how it works?

[marc weber]

Originally posted by liqiang yang:
Thanks Frank, Can you explain a little bit, how it works?

If you place the statement inside braces within the class body, the block of code will execute when the class is initialized. This will allow your code to compile, but you won't see any output until an instance of the method local class is created. You could also place the statement inside a method, as I suggested above.

public class Test {
  public static void main(String[] args) {
    final int a = 1;
    class MethodLocalClass {
      {
        System.out.println("  Initializer block: " + a);
      }
 
      void meth() {
        System.out.println("  Method: " + a);
      }
    }
    System.out.println("Creating new instance...");
    MethodLocalClass c = new MethodLocalClass();
    System.out.println("Calling method...");
    c.meth();
  }
}

[ March 18, 2008: Message edited by: marc weber ]