java.util.NoSuchElementException: No line found

Question

I got an run time exception in my program while I am reading a file through a Scanner.

java.util.NoSuchElementException: No line found         at java.util.Scanner.nextLine(Unknown Source)        at Day1.ReadFile.read(ReadFile.java:49)      at Day1.ParseTree.main(ParseTree.java:17)  

My code is:

while((str=sc.nextLine())!=null){     i=0;     if(str.equals("Locations"))     {         size=4;         t=3;         str=sc.nextLine();         str=sc.nextLine();     }     if(str.equals("Professions"))     {         size=3;         t=2;         str=sc.nextLine();         str=sc.nextLine();     }     if(str.equals("Individuals"))     {         size=4;         t=4;         str=sc.nextLine();         str=sc.nextLine();     }  int j=0; String loc[]=new String[size]; while(j<size){     beg=0;     end=str.indexOf(',');     if(end!=-1){         tmp=str.substring(beg, end);         beg=end+2;     }     if(end==-1)     {         tmp=str.substring(beg);     }     if(beg<str.length())         str=str.substring(beg);     loc[i]=tmp;     i++;      if(i==size ){         if(t==3)         {             location.add(loc);         }         if(t==2)         {             profession.add(loc);         }         if(t==4)         {             individual.add(loc);         }         i=0;     }     j++;     System.out.print("\n"); } 

Answer 1

with Scanner you need to check if there is a next line with hasNextLine()

so the loop becomes

while(sc.hasNextLine()){     str=sc.nextLine();     //... } 

it's readers that return null on EOF

ofcourse in this piece of code this is dependent on whether the input is properly formatted

Answer 2

You're calling nextLine() and it's throwing an exception when there's no line, exactly as the javadoc describes. It will never return null

https://docs.oracle.com/javase/8/docs/api/java/util/Scanner.html