Exceptions & File I/O:Read

Question 1

compile-time error

Answer 1

occurs when there is a syntactical error or the compiler identifies code that cannot execute

Question 2

run-time error

Answer 2

occurs while the program is executing when it is asked to access memory that is inaccessible or perform an operation of which it is not capable
Run-time errors often result in an Exception

Question 3

Throwables

Answer 3

Exceptions and Errors

Question 4

Errors

Answer 4

sed by the JVM to indicate errors that are associated with the runtime environment, such as running out of memory or other resources. Errors occur only at runtime and it is not possible for an application recover from these errors

Question 5

Exceptions

Answer 5

anomalous situations that occur while a program is executing

Question 6

Checked Exceptions

Answer 6

must be caught with a try…catch.
When calling a method that has a checked exception then the possible exception it can throw must either be caught and dealt with using a try…catch or the method calling it must itself throw an exception of that type.

Question 7

Runtime Exceptions

Answer 7

can be thrown from any method and do not have to caught with a try…catch.

Question 8

Exception Handling

Answer 8

dealing with unexpected problems in an application so the program does not crash.

Question 9

Stack Trace

Answer 9

details about what happened and where it occurred in the code

Question 10

Try…Catch Block

Answer 10

Risky code is surrounded with a try…catch. The try identifies a block of code that may cause an exception, and the catch block identifies a block of code to run if an exception occurs. When an exception occurs in the try, all following lines of code are skipped and the catch is immediately executed

Question 11

Throw and Throws

Answer 11

Exceptions can be thrown manually using the throw keyword.  The throw keyword is a statement of code.
	throw new MyException();

A method may indicate that it can thrown a checked exception using the throws keyword. The throws keyword is part of the method signature.
public void myMethod() throws MyException

Question 12

Call Stack.

Answer 12

When an Exception is thrown it is passed up through each level of the call stack. At each level it can be caught and handled by a try…catch().

Question 13

File Modes

Answer 13

Indicates a File
      d     Indicates a directory
      l      Indicates a Link
-rwxrwxrwx
R - Read
W - write
X - execute

Question 14

-RWXrwxrwx

Answer 14

r   has read permission
w  has write permission
x   has execute permission
-    does not have this permission for the slot it is in. 
First Group is for the Owner of the File

Question 15

-rwxRWXrwx

Answer 15

Second Group is for users that are members of the same user group as the owner of the file

Question 16

-rwxrwxRWX

Answer 16

Third Group is for all other users

Question 17

File Operations

Answer 17

exists()
isDirectory()
isFile()
getName()
getAbsolutePath()
mkdir()
createNewFile()

Question 18

exists()

Answer 18

boolean - does the file or directory exist

Question 19

isDirectory()

Answer 19

boolean - returns true if the path points to a directory

Question 20

isFile()

Answer 20

boolean - returns true if the path points to a file

Question 21

getName()

Answer 21

Returns the name of the file or directory

Question 22

getAbsolutePath()

Answer 22

Returns the absolute path of the file or directory

Question 23

mkdir()

Answer 23

Creates a new directory in the specified location

Question 24

createNewFile()

Answer 24

Creates a new File in the specified location