In Java, what is the difference between catch a generic exception and a specific exception (eg. IOException?)

Question

Currently I\'m catching only generic exceptions, but i want change this to catch the specific exceptions, but what is the advantage of this?

Answer 1

Take this example:

try {
 StringBuffer fileData = new StringBuffer(1000);
 BufferedReader reader = new BufferedReader(
   new FileReader(filePath));
 char[] buf = new char[1024];
 int numRead=0;
 while((numRead=reader.read(buf)) != -1){
   fileData.append(buf, 0, numRead);
 }
 reader.close();
 return fileData.toString();
} catch (Exception e) {
 //do something generic - maybe log it
}

As it stands, it works...usually. However, with the vague error catching I can't really do anything except warn the user. If I caught the FileNotFoundException specifically, I could try another file. If I caught the IOException specifially, I could warn about something else. This example is a bit weak, but it may give you some idea.