привет.помогите.почему double tmp1 = Double.parseDouble(y1); и double tmp2 = Double.parseDouble(y2); не выдят переменную y1 и y2 то есть почему эти строки визивают ошибку

import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.lang.*;
public class godmos{
private Double delet(StringBuffer r2){
           String r=r2.toString();


           String[] words = r.split("/",2);
           Pattern   p ,p1;
           Matcher   m ,m1;
           p = Pattern.compile("\\d*$");
           m = p.matcher(words[0]);
           p1 = Pattern.compile("^\\d*");
           m1 = p1.matcher(words[1]);
           while (m.find() ){
           String y1=m.group();

          }
           while ( m1.find()){
           String y2=m1.group();
          }
		   double tmp1 = Double.parseDouble(y1);
		   double tmp2 = Double.parseDouble(y2);
		   return tmp1/tmp2;
}
private Double doubleplus(StringBuffer r2){
           String r=r2.toString();

           String[] words1 = r.split("*",2);
           Pattern   p ,p1;
           Matcher   m ,m1;
           p = Pattern.compile("\\d*$");
           m = p.matcher(words1[0]);
           p1 = Pattern.compile("^\\d*");
           m1 = p1.matcher(words1[1]);
           while (m.find() ){
           String y1=m.group();
          }
           while ( m1.find()){
           String y2=m1.group();
          }
		   double tmp1 = Double.parseDouble(y1);
		   double tmp2 = Double.parseDouble(y2);
		   return tmp1*tmp2;
}
private Double plus(StringBuffer r2){
           String r=r2.toString();

           String[] words1 = r.split("+",2);
           Pattern   p ,p1;
           Matcher   m ,m1;
           p = Pattern.compile("\\d*$");
           m = p.matcher(words1[0]);
           p1 = Pattern.compile("^\\d*");
           m1 = p1.matcher(words1[1]);
           while (m.find() ){
           String y1=m.group();
          }
           while ( m1.find()){
           String y2=m1.group();
          }
		   double tmp1 = Double.parseDouble(y1);
		   double tmp2 = Double.parseDouble(y2);
		   return tmp1+tmp2;
}
private Double minus(StringBuffer r2){
           String r=r2.toString();

           String[] words1 = r.split("*",2);
           Pattern   p ,p1;
           Matcher   m ,m1;
           p = Pattern.compile("\\d*$");
           m = p.matcher(words1[0]);
           p1 = Pattern.compile("^\\d*");
           m1 = p1.matcher(words1[1]);
           while (m.find() ){
           String y1=m.group();
          }
           while ( m1.find()){
           String y2=m1.group();
          }
		   double tmp1 = Double.parseDouble(y1);
		   double tmp2 = Double.parseDouble(y2);
		   return tmp1*tmp2;
}



	public String str1 = "5+7-9/9*2/4*3 ";
	StringBuffer str0 = new StringBuffer(str1);
	public  StringBuffer  calculate (StringBuffer str)

	 {


	        while(str.indexOf("/")!=-1 | str.indexOf("*")!=-1 ){

		 if(str.indexOf("/") < str.indexOf("*") && str.indexOf("/")!=-1)
	   {   int a1 = str.indexOf("/");
		   int a2 = a1+1;
		   int a3 = a1-1;
		   double tmp3=delet(str);
	       str.delete(a3,a2+1);
	       str.insert(a3,tmp3);
		 }
		 if(str.indexOf("*") < str.indexOf("/") && str.indexOf("*")!=-1)
	   {   int a4 = str.indexOf("*");
		   int a5 = a4+1;
		   int a6 = a4-1;
		   double tmp6=doubleplus(str);
	       str.delete(a6,a5+1);
	       str.insert(a6,tmp6);
		 }

		 }

            while(str.indexOf("+")!=-1 | str.indexOf("-")!=-1 ){

		 if(str.indexOf("+") < str.indexOf("-") && str.indexOf("+")!=-1 )
	   {   int a11 = str.indexOf("+");
		   int a21 = a11+1;
		   int a31 = a11-1;
		   double tmp31=plus(str);
	       str.delete(a31,a21+1);
	       str.insert(a31,tmp31);
		 }
		 if(str.indexOf("-") < str.indexOf("+") && str.indexOf("-")!=-1)
	   {   int a41 = str.indexOf("-");
		   int a51= a41+1;
		   int a61 = a41-1;
		   double tmp61=minus(str);
	       str.delete(a61,a51+1);
	       str.insert(a61,tmp61);
		 }
		 }
		    return str;
	}

	StringBuffer f1 = calculate(str0);


	public static void main (String[] args) {
		godmos gm = new godmos();
        System.out.print(gm.f1);



	}
}