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Exceptions
What Is an Exception?
The Catch or Specify Requirement
Catching and Handling Exceptions
The try Block
The catch Blocks
The finally Block
The try-with-resources Statement
Putting It All Together
Specifying the Exceptions Thrown by a Method
How to Throw Exceptions
Chained Exceptions
Creating Exception Classes
Unchecked Exceptions — The Controversy
Advantages of Exceptions
Summary
Questions and Exercises
Trail: Essential Classes
Lesson: Exceptions
Section: Catching and Handling Exceptions
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# The try Block

The first step in constructing an exception handler is to enclose the code that might throw an exception within a `try` block. In general, a `try` block looks like the following:

    try {
        code
    }
    catch and finally blocks . . .

The segment in the example labeled `code` contains one or more legal lines of code that could throw an exception. (The `catch` and `finally` blocks are explained in the next two subsections.)

To construct an exception handler for the `writeList` method from the `ListOfNumbers` class, enclose the exception-throwing statements of the `writeList` method within a `try` block. There is more than one way to do this. You can put each line of code that might throw an exception within its own `try` block and provide separate exception handlers for each. Or, you can put all the `writeList` code within a single `try` block and associate multiple handlers with it. The following listing uses one `try` block for the entire method because the code in question is very short.

    private List<Integer> list;
    private static final int SIZE = 10;

    public void writeList() {
        PrintWriter out = null;
        try {
            System.out.println("Entered try statement");
            out = new PrintWriter(new FileWriter("OutFile.txt"));
            for (int i = 0; i < SIZE; i++) {
                out.println("Value at: " + i + " = " + list.get(i));
            }
        }
        catch and finally blocks  . . .
    }

If an exception occurs within the `try` block, that exception is handled by an exception handler associated with it. To associate an exception handler with a `try` block, you must put a `catch` block after it; the next section, The catch Blocks, shows you how.

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