The first step in constructing an exception handler is to enclose the statements that might throw an exception within a
try
block. In general, a try
block looks like this:The segment of code labelled Java statements is composed of one or more legal Java statements that could throw an exception.To construct an exception handler for thetry { Java statements }
writeList
method from the ListOfNumbers
class, you need to enclose the exception-throwing statements of the writeList
method within a try
block. There is more than one way to accomplish this task. You could put each statement that might potentially throw an exception within its own try
statement, and provide separate exception handlers for each try
. Or you could put all of the writeList
statements within a single try
statement and associate multiple handlers with it. The following listing uses one try
statement for the entire method because the code tends to be easier to read.ThePrintWriter out = null; try { System.out.println("Entering try statement"); out = new PrintWriter( new FileWriter("OutFile.txt")); for (int i = 0; i < size; i++) out.println("Value at: " + i + " = " + victor.elementAt(i)); }
try
statement governs the statements enclosed within it and defines the scope of any exception handlers associated with it. In other words, if an exception occurs within the try
statement, that exception is handled by the appropriate exception handler associated with this try
statement.A try
statement must be accompanied by at least one catch
block or one finally
block.
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