java cannot find symbol error -

i had error although compiled semester1 class , @ same package

public class semester2{  string subjects2[] = {"arabic 2","islamic 2","english 2","calculas","java1","manegment","physecs2"};         double degrees2[] = new double [7];         int hours2[] = {2,2,2,4,4,2,3};         double subjectpoint2[] = new double[7];                 string[]estimate2 = new string[7];                 double fulldegree2 = 0;                 int fail2 = 0;  //fail subjects         public semester2(){         }         public semester2(double degrees2[],string subjects2[]){                     for(int i=0;i<7;i++){                         .degrees2[i] = degrees2[i];                         subjectpoint2[i] = degrees2[i] / 25;                          fulldegree2 = 0;                         fail2 = 0;                     } //end of        } //end of constructer                  public double semester2method(double degrees2[],string subjects2[],string[]estimate2,double fulldegree2,int fail2,double subjectpoint2[],int hours2[]){                      for(int i=0;i<7;i++){                         if ((degrees2[i] > 100)|(degrees2[i] < 0)){                          system.out.println("this degree imposible");                          i--;                          continue;                      } //end of if                if (degrees2[i] < 40)                  fail2 ++;                else                   if (subjectpoint2[i] >= 3.6)                    estimate2[i]="a+";                   if (subjectpoint2[i] >= 3.2)                    estimate2[i] = "a";                     if (subjectpoint2[i] >= 2.8)                    estimate2[i] = "b+";                    if (subjectpoint2[i] >= 2.6)                    estimate2[i] = "b";                    if (subjectpoint2[i] >= 2.4)                    estimate2[i] = "c+";                    if (subjectpoint2[i] >= 2.0)                    estimate2[i] = "c";                    if (subjectpoint2[i] >= 1.6)                    estimate2[i] = "d";                    else                     estimate2[i] = "f";                   fulldegree2 += subjectpoint2[i] * hours2[i];                   }//end of                  semester1 [] obj=new semester1[2];                   obj[0]=new semester1();                   obj[1]=new semester1(degrees[7],subjects[7]);                  //semester1 obj = new semester1();                   double avarge = fulldegree2 /19;                  double cavarge=( fulldegree2 + obj[1].fulldegree )/( 21 + 19 );                  return cavarge;               } //end of method          } //end of semester2 

here error error: cannot find symbol

semester1 [] obj=new semester1[2];                  ^ 

your semester1.java file has not been compiled, can guess comments. need first compile file. create semester1.class file. should compile semester2.java. think should work.