array confusion

Question about two peices of code
1.

Code:

---

{
                int i=0;
                int j=0;
                int total=0;
                while(Character.isWhitespace(lines[i].charAt(j)))
                {
                        total++;
                        i++;
                        j++;
                }
                return total;

---

this should show the number of characters in an already loadaded file but it doesnt

2How do you take a file with blank lines in it and crunch it up for example
this is

a file

now
should turn into

this
is
a file
now

I)

Code:

---

int total=0;
for (int lineIndex=0; lineIndex < lines.length; lineIndex++) {
        String str = lines[lineIndex];       
        if ( int j = 0; j < str.length; j++ ) {
                if (!Character.isWhitespace(str.charAt(j))) { // if you do not want to calculate whitespaces
                        total++;
                }
        }
}

---

II)

Code:

---

BufferedReader br = new BufferedReader(XXX); // XXX - your input stream e.g. FileInputStream
 String line;
 while ((line = br.readLine()) != null) {
      if (line.trim().size()str == 0) {
              continue; // skip empty string
      }
      ....     
 }

---

Can you show it without continue and also your the first one doesnt work

Code:

---

for (int lineIndex=0; lineIndex < lines.length; lineIndex++) {
        String line = lines[lineIndex];       
        if (!line.trim().size() == 0) {
                System.out.println(line);
...

  }
}

---

the character count one doesnt work either

Code:

---

{
                int i=0;
                int j=0;
                int total=0;
                while(Character.isWhitespace(lines[i].charAt(j)))
                {
                        total++;
                        i++;
                        j++;
                }
                return total;

---

The character count:

Code:

---

int total = 0;
        String[] lines = new String[] {
                "abcdef", "123", "qwer ty" // 15 chars + 1 space
        };
        for (int lineIndex=0; lineIndex < lines.length; lineIndex++) {
            String str = lines[lineIndex];
            for (int j = 0; j < str.length(); j++ ) {
                if (!Character.isWhitespace(str.charAt(j))) { // if you do not want to calculate whitespaces
                    total++;
                }
            }
        }
        System.out.println(total);

---

do you know what a nullpointer exception is

Second example:

Code:

---

String[] lines = new String[] {
                "this", "  ", "is", "a" , " ",  "test" };
        for (int lineIndex=0; lineIndex < lines.length; lineIndex++) {
            String line = lines[lineIndex];
            if (!(line.trim().length() == 0)) {
                System.out.println(line);
            }
        }

---

PS: I often post a programs which I don't check. I think small errors like misprints you can correct yourself.

Quote:

---

Originally Posted by torrinment

do you know what a nullpointer exception is

---

Yes I know. It happens when you try to do with something that don't exsists.

For example:
String s = null;
s.trim(); // throws NullPointerException

that works but gives me a nullpointerexception how do i fix this like it does what it supposed to but then i get that exceptio n

Quote:

---

Originally Posted by torrinment

that works but gives me a nullpointerexception how do i fix this like it does what it supposed to but then i get that exceptio n

---

It's difficult to answer because I don't know your code. Please attach a whole your application or am exception stack trace.

BTW: check that you nowhere set empty values to variables.

no im just talkin about both the character count you showed me and the eliminate vspace

Code:

---

public static int charCount(String[]lines)
        {
                int total = 0;
              for (int i=0; i < lines.length; i++)
              {
                      for (int j = 0; j < lines[i].length(); j++ )
              {
                      if (!Character.isWhitespace(lines[i].charAt(j))) {
                              total++;
                        }
                    }
                }
                System.out.println(total);
                return total;
        }

---

and

Code:

---

public static void EliminateVSpace(String[]lines)
        {
        for (int lineIndex=0; lineIndex < lines.length; lineIndex++) {
            String line = lines[lineIndex];
            if (!(line.trim().length() == 0)) {
                System.out.println(line);
            }
        }

---

}

I understand. The exception happens because you pass lines with empty values.
For example
if you pass such array:
String[] lines = new String[] {"this", " ", "is", null, "a", "test" };
it will produce an exception.

so i fix it by...