java.text.MessageFormat
format(Object single, StringBuffer result, FieldPosition ignore) doesn't
work, get the following exception thrown when program is run:

Exception in thread "main" java.lang.ClassCastException: java.lang.Double
at java.text.MessageFormat.format(Compiled Code)

The problem is with the 1st param Object single. See suggested fix.
The other 3 forms of this method work OK.


Test program: Testit.java

/*
 * Test for MessageFormat.format
 *
 * public final StringBuffer format(Object source,
 * StringBuffer result, FieldPosition ignore)
 *
 * Formats message pattern to produce a string.
 *
 */

 import java.util.*;
 import java.io.*;
 import java.lang.*;
 import java.text.*;

 class Testit
 {
    public static void main(String arg[])
    {
     String sExpect = "The disk C contains 45 file(s).";
        MessageFormat mf = new MessageFormat("The disk C contains {0} file(s).");
        StringBuffer sb1 = new StringBuffer("");
        Object obj = new Double(45);
        StringBuffer sb2 = mf.format(obj, sb1, null);
        System.out.println(sb2);
        if ( sb2.toString().equals(sExpect) ) {
          System.out.println("Test Passed");
        } else {
          System.out.println("Test Failed");
        }
    }
 }


Output from run:
Exception in thread "main" java.lang.ClassCastException: java.lang.Double
at java.text.MessageFormat.format(Compiled Code)
at Testit.main(Compiled Code)


Output with applied fix:
The disk C contains 45 file(s).
Test Passed