Java Try and Catch IOException must be caught or declared to be thrown

Question

I am trying to use a bit of code I found at the bottom of this page. Here is the code in a class that I created for it: ``` import java.io.LineNumberReader; import java.io.FileReader; import java.io.IOException; public class LineCounter { public static int countLines(String filename) throws IOException { LineNumberReader reader = new LineNumberReader(new FileReader(filename)); int cnt = 0; String lineRead = ""; while ((lineRead = reader.readLine()) != null) {} cnt = reader.getLineNumber(); reader.close(); return cnt; } } ``` My objective is to count the lines of a text file, store that number as an integer, then use that integer in my main class. In my main class I tried a few different ways of making this happen, but (being a new programmer) I am missing something. Here is the first thing I tried: ``` String sFileName = "MyTextFile.txt"; private int lineCount = LineCounter.countLines(sFileName); ``` With this attempt I get the error "unreported exception java.io.IOException; must be…

Accepted Answer

Initializer block is just like any bits of code; it's not "attached" to any field/method preceding it. To assign values to fields, you have to explicitly use the field as the lhs of an assignment statement.

```
private int lineCount; {
    try{
        lineCount = LineCounter.countLines(sFileName);
        /*^^^^^^^*/
    }
    catch(IOException ex){
        System.out.println (ex.toString());
        System.out.println("Could not find file " + sFileName);
    }
}
```

Also, your `countLines` can be made simpler:

```
  public static int countLines(String filename) throws IOException {
    LineNumberReader reader  = new LineNumberReader(new FileReader(filename));
    while (reader.readLine() != null) {}
    reader.close();
    return reader.getLineNumber();
  }
```

Based on my test, it looks like you can `getLineNumber()` after `close()`.

Java Try and Catch IOException must be caught or declared to be thrown

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