11 - Exceptions

Question 1

Errors and exceptions are objects that …

Answer 1

represent unusual or invalid processing.

Question 2

Error represents an …

Answer 2

unrecoverable situation and should not be caught.

Question 3

Three ways to deal with exceptions.

Answer 3

• not handle the exception at all
• handle the exception where it occurs,
• handle the exception at another point in the program.

Question 4

call stack trace

Answer 4

The messages printed when an exception is thrown provides a method call stack trace.

Question 5

try-catch statement

Answer 5

A try-catch statement identifies a block of statements that may thrown an exception.

• each catch clause is called an exception handler
• finally clause is executed wither the try block is exited normally or because of a thrown exception.

Question 6

If an exception is not caught and handled it?

Answer 6

it is propagated to the calling method.

Question 7

A new exception is defined by deriving a…

Answer 7

new class from the Exception class or one of its decedents.

Question 8

Checked exceptions must either …

Answer 8

be caught by a method or must be listed in the throws clause of any method that may throw or propagate it.

Question 9

throws

Answer 9

throws clause is appended to the header of a method definition to formally acknowledge that the method will throw or propagate a particular exception if it occurs.

Question 10

Unchecked exception requires …

Answer 10

throws clause

Question 11

The only unchecked exceptions in Java are

Answer 11

objects of type RuntimeException or any of its decendents.

Question 12

A stream is…

Answer 12

a sequential sequence of bytes; it can be used as a source of input or a destination for output.

Question 13

Three public reference variables in the System class represent the standard I/O streams.

Answer 13

• System.in = standard input stream
• System.out = standard output stream.
• System.err = standard error stream (output for error messages)