COMPROG

• Volatile storage is temporary. Volatile values (stored in variables) are lost when the computer loses its power.
• o Non-volatile storage is permanent. A Java program that is saved on a disk uses a non-volatile storage.
• RAM stands for Random Access Memory
• a text file consists of data that can be read in a text editor
• a binary file contains data that is not encoded as text
• permanent files are stored in main directory or root directory
• directories in which files are located are called path
• (\) path delimiter is special character used to seperate used to seperate path components
• path class creates objects that contain information about files and directories, such as sizes, locations, creation dates, and is used to check whether a file or directory exists.
• files class performs operations on files and directories, such as determining their attributes, creating input and output streams, and deleting them.
• to use both path and file classes, add the following statement. import java.nio.file.*;
• to create and define a path. Path filePath = Paths.get("asdasd\\asda\\asdasd");
• absolute path is a complete path; does not need any information
• relative path depends on other information
• String toString() Returns the String representation of the Path, eliminating double backslashes
• Path getFileName() Returns the file or directory denoted by this Path; this is the last item

  in the sequence of name elements.
• int getNameCount() Returns the number of name elements in the Path
• PathgetName() Returns the name in the position of the Path specified by the integer parameter
• convert relative path to absolute path. toAbsolutePath()
• delete() method of the Files class accepts a Path parameter and removes the last element
• To retrieve useful information about a file, the readAttributes() method of the Files class is used.
• A character can be any letter, number, or other special symbol (such as punctuation mark) that makes up data.
• field is a group of characters that has some meaning.
• record is a collection of fields that contain data about an entity
• file consists of related records
• readAttributes method takes 2 arguments
• A stream is a flow of data.
• · Flushing clears any bytes that have been sent to a buffer for output but have not yet been displayed on a hardware device.
• An exception is an event that occurs during the execution of a program that disrupts the normal flow of instructions.
• Exception handling is the process used to change the normal flow of code execution if a specified exception occurs.
• Exceptions that occur during compilation are called checked exceptions
• Unchecked exceptions are exceptions that occur during execution.
• ClassNotFoundException

  The class is not found.
• IllegalAccessException

  Access to a class is denied.
• InstantiationException

  Attempt to create an object of an abstract class or an interface.
• NoSuchMethodException

  A requested method does not exist.
• ArrayIndexOutOfBoundsException

  Accessing an invalid index of the array
• ArithmeticException

  Arithmetic error, such as an integer divided by 0
• NumberFormatException

  Invalid conversion of a string to a numeric format
• ·A try block is a block of code that might throw an exception that can be handled by a matching catch

  block.