How much code to put in try-catch block [closed]

Question

Is there a "best practice" for how much code to put inside a try/catch block?

I have posted 3 different scenarios below.

I did not include behavior in each catch block and i did not include the finally block. This was to improve readability for viewers. Assume each catch does something differently. And assume the finally will be closing the stream. Just trying to create an easy to read example for future readers.

1. Control, no try/catch.
2. Code with 1 try/catch for each place needed.
3. Code with only 1 try/catch surrounding whole code block.

What is generally accepted as the best practice and why?

---

Scenario 1

Code without try/catch, just for control.

    BufferedReader bufferedReader = new BufferedReader(new FileReader("somepath"));
    String line;
    while ((line = bufferedReader.readLine()) != null) {
        Object object = new Object();
        this.doSomething(object);
    }
    bufferedReader.close();

---

Scenario 2

Code with a try/catch block for each individual place needed.

    BufferedReader bufferedReader = null;
    try {
        bufferedReader = new BufferedReader(new FileReader("somepath"));
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
    String line;
    try {
        while ((line = bufferedReader.readLine()) != null) {
            Object object = new Object();
            this.doSomething(object);
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
    try {
        bufferedReader.close();
    } catch (IOException e) {
        e.printStackTrace();
    }

---

Scenario 3

Code with 1 try/catch surrounding the whole block of code.

    try {
        BufferedReader bufferedReader = new BufferedReader(new FileReader("somepath"));
        String line;
        while ((line = bufferedReader.readLine()) != null) {
            Object object = new Object();
            this.doSomething(object);
        }
        bufferedReader.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

Answer 1

You should scope your try/catches based on the following criteria:

• do you need to do different things based on where the exception came from?
• do you need to do different things based on which exception was thrown?
• what code needs to be skipped (aka is "invalid") when a given exception is thrown?

answering these questions will enable you to determine the appropriate scope for any try/catch block.