Java - An Object Oriented Programming Language

Java - An Object Oriented Programming Language

1. OOP - Programming using objects

   • Encoding Sets - "Languages" code is programmed in, also includes data compression techniques.
     • ASCII - Encoding set supported by Java, 128 character set
       • Extended ASCII - 128 additional characters
     • ISO-8859-1 (Latin 1) - Character set for European languages.
     • Unicode - Includes all characters in all languages, used in Java.
       • UTF-8, UTF-16, UTF-32 - Types of data compression in Unicode for8-bit, 16-bit, and 32-bits per character.
   • Primitives - Non-objects, true or false. 8 primitive types.
     • Primitive Conversion - Changing a primitive's type
     • byte - 8 bits
     • short - 16 bits
     • int - 32 bits
     • long - 64 bits
     • float - 32 bits IEEE 754, single precision
     • double - 64 bit IEEE 754, double precision
     • char - Unicode character
     • boolean - True or false
   • Variables - Place holder with changing values and must have a declared data type
     • Data types in Java: Reference and Primitive
       • Reference type: Refers to object
       • Primitive type: Holds a primitive
     • Identifier- Required part of variable that begins with a Java letter (a name)
       • Java letter - Upper and lowercase ASCII Latin letters
         • Java digit - ASCII digits 0-9
     • Sun's Naming Convention for Variables - Lowercase letter for starting first word, capital for the rest.
   • Constants - Place holders with values that don't change. Names are uppercase with words separated by underscores.
     • Keyword final - Used to declare a constant
   • Literals - Source code that represents data values. 3 types of literals.
     • Literals of Primitive Types - 4 subtypes
       • Integer literals - Written in decimal, hexadecimal, or octal. Assign values to variables with the data types of byte, short, int, and long.
       • Floating point literals - Divided into parts of a whole number, decimal, fractional, and operation.
       • Character literals - Unicode character or escape sequence placed in single quotes.
         • Escape sequence - Represents a Unicode character that can't be input with a keyword, or has a special function.
       • Boolean literals - 2 values; true and false.
     • String literals
     • Null literal
   • Operators - Notate operations a program performs

2. Separators - Used in Java to separate and define parts of code.

   • Parenthesis - (), used in method signatures
   • Braces - {}, declare types
   • Angle brackets - <>, pass paramater to parametrized types
   • Semicolon - ;, Terminate statements
   • Colon - :, Separates arguments
   • Period - ., Separate package names from subpackages