public static boolean isNumeric(String stringToTest)

public class Tester
{  
public static void main(String[] args)  
{    
String[] stringArray = {"A total String", "A 123", "123oStart", "2", "2.3", "2.3.2", "2..3", ".2", ".X", "123.456"};	
for(int i = 0; i < stringArray.length; i++)	  
System.out.println(isNumber(stringArray[i]));  
}  
 
public static boolean isNumber(String input)  
{    
  boolean decimalAlreadyUsed = false;    
  char[] charArray = input.toCharArray();        
  for(int i = 0; i < charArray.length; i++)    {      
    boolean isDigit = Character.isDigit(charArray[i]);      
    if(isDigit)      {         
      continue;      } 
	else {        
      if(charArray[i] == '.')        {	  
        if(decimalAlreadyUsed)	  {            
          return false;          } 
		else {            
          decimalAlreadyUsed = true;          
		}        
      }else{          
	    return false;        
	  }      
	}//end of if/else    
  }//end of for loop    
  return true;  
}//end of method isNumber};
}//end of class

> Sure you could write a method using the wrapper methods
> you listed as long as you are use try/catch blocks to
> catch the NumberFormatExceptions that will be thrown.

> The issue really is whether you should.  I think that it
> is generally viewed that exceptions should be used for
> exceptional events, not to control the flow of a program.

> If I remember correctly the Joshua Bloch "Effective Java"
> book has an item on this, pretty much saying the same
> thing.  I don't have the book in front of me so I can't be
> more specific.

import java.io.PrintStream;
 
public class BadUseOfException
{
   public static void main(String args[])
   {
      printNumberList( new int []{ 4, 3, 2, 1 }, System.out );
   }
 
   static void printNumberList( int [] numbers, PrintStream stream )
   {
      try
      {
         for( int i = 0; i < Integer.MAX_VALUE; i++ )
            stream.println( i + ". " + numbers[i] );
      }
      catch( ArrayIndexOutOfBoundsException aioobe )
      {
         stream.println("That's all, folks!");
      }
   }
}