String Validation using Regular Expression

Validate String Number

public class ValidateStrNum {

 public static boolean validateNumber(String number) { 
  return number.matches("^\\d*$"); 
 }
 
 public static boolean validateDouble(String number) { 
  return number.matches("\\d+\\.\\d+"); 
 }
 
 public static boolean validateHex(String number) { 
  return number.matches("^(0x|0X)[0-9A-Fa-f]+"); 
 }
   
 public static void main(String[] args) {
  String str = "1234567890";
       
  if(validateNumber(str)){
   try{
    if(str.length() <= 10){
     Integer i = Integer.parseInt(str);
     System.out.println("Int: "+i);
    }else{
     Long l = Long.parseLong(str);
     System.out.println("Long: "+l);
    }
   }catch(Exception e){
    e.printStackTrace();
   }
   // System.out.println(str);
   
  }else{
   System.out.println("numeric error");
  }
  
  if(validateDouble(str)){
   
    System.out.println(str);
   
  }else{
   System.out.println("double error");
  }
  
  if(validateHex(str)){
   
    System.out.println(str);
   
  }else{
   System.out.println("Hex error");
  }

 }
 
}