null pointer exception comparing two strings in java.
- by David
I got this error message and I'm not quite sure whats wrong:
Exception in thread "main" java.lang.NullPointerException
at Risk.runTeams(Risk.java:384)
at Risk.blobRunner(Risk.java:220)
at Risk.genRunner(Risk.java:207)
at Risk.main(Risk.java:176)
Here is the relevant bits of code (i will draw attention to the line numbers within the error message via comments in the code as well as inputs i put into the program while its running where relevant)
public class Risk
{
...
public static void main (String[]arg)
{
String CPUcolor = CPUcolor () ;
genRunner (CPUcolor) ; //line 176
...
}
...
public static void genRunner (String CPUcolor) // when this method runs i select 0 and run blob since its my only option. Theres nothing wrong with this method so long as i know, this is only significant because it takes me to blob runner and because another one of our relelvent line numbers apears.
{
String[] strats = new String[1] ;
strats[0] = "0 - Blob" ;
int s = chooseStrat (strats) ;
if (s == 0) blobRunner (CPUcolor) ; // this is line 207
}
...
public static void blobRunner (String CPUcolor)
{
System.out.println ("blob Runner") ; int turn = 0 ; boolean gameOver = false ;
Dice other = new Dice ("other") ;
Dice a1 = new Dice ("a1") ; Dice a2 = new Dice ("a2") ; Dice a3 = new Dice ("a3") ;
Dice d1 = new Dice ("d1") ; Dice d2 = new Dice ("d2") ;
space (5) ;
Territory[] board = makeBoard() ;
IdiceRoll (other) ;
String[] colors = runTeams(CPUcolor) ; //this is line 220
Card[] deck = Card.createDeck () ;
System.out.println (StratUtil.canTurnIn (deck)) ;
while (gameOver == false)
{
idler (deck) ;
board = assignTerri (board, colors) ;
checkBoard (board, colors) ;
}
}
...
public static String[] runTeams (String CPUcolor)
{
boolean z = false ;
String[] a = new String[6] ;
while (z == false)
{
a = assignTeams () ;
printOrder (a) ;
boolean CPU = false ;
for (int i = 0; i<a.length; i++)
{
if (a[i].equals(CPUcolor)) CPU = true ; //this is line 384
}
if (CPU==false)
{
System.out.println ("ERROR YOU NEED TO INCLUDE THE COLOR OF THE CPU IN THE TURN ORDER") ;
runTeams (CPUcolor) ;
}
System.out.println ("is this turn order correct? (Y/N)") ;
String s = getIns () ;
while (!((s.equals ("y")) || (s.equals ("Y")) || (s.equals ("n")) || (s.equals ("N"))))
{
System.out.println ("try again") ;
s = getIns () ;
}
if (s.equals ("y") || s.equals ("Y") )
z = true ;
}
return a ;
}
...
} // This } closes the class
The reason i don't think i should be getting a Null:pointerException is because in this line: a[i].equals(CPUcolor) a at index i holds a string and CPUcolor is a string. Both at this point definatly have a value neither is null. Can anyone please tell me whats going wrong?
