OCA JAVA Training Material Talking about Programming with Java Operators - Understanding Fundamentals Operators - Understanding Operator Precedence Slides based in the book: "OCA Java SE 7 Programmer I Study Guide (Examn 1Z0-803)"

1. 3. Programming with
Java Operators
• Understanding Fundamentals Operators
• Understanding Operator Precedence
By Fernando Gil
Date: Jan 2015
Version: 1.0
Based in the book OCA Java SE 7 Programmer I Study Guide (Examn 1Z0-803)

2. 1. Understanding Fundamental
Operators
• Java operators are used to return a result from an
expression using one, two, or three operands
• Operands are the values placed to the right or left side of
the operators
• Prefix/postfix – increment/decrement operators use one
operand
• The conditional ternary operator (?:) uses three operands
• All other operators use two operands

4. Assignment Operators
• Assignment operators are used to assign values
to variables
• The assignment operator by itself is the equal
sign
• At it simplest, the assignment operator moves
valid literals into variables
• Assignment operators cause compiler errors
when the literals are not valid for the variable to
which they are assigned

5. Compound Assignment
Operators
• Compound assignment operators provide a shorter
syntax for assigning the result of an arithmetic or bitwise
operator
• They perform the operation on the two operands before
assigning the result to the first operand
• There are 11 compound assignment operators
• While the use of compound assignment operators cuts
down on keystrokes, it is generally good practice to use
the longhand approach since the code is clearly more
readable

6. Operator Function
+= Assigns the result of the addition
- = Assigns the result of the subtraction
*= Assigns the result of the multiplication
/= Assigns the result of the division
%= Assigns the remainder of the division
&= Assigns the result of the logical AND
|= Assigns the result of the logical OR
^= Assigns the result of the logical XOR
<<= Assigns the result of the signed left bit shift
>>= Assigns the result of the signed right bit shift
>>>= Assigns the result of the unsigned right bit shift

7. Basic Arithmetic Operators
Operator Function
+ Addition (sum) operator
- Subtraction (difference) operator
* Multiplication (product) operator
/ Division (quotient) operator
% Modulus (remainder) operator
int totalCannonBalls = greyCannonBalls + blackCannonBalls;

8. Prefix and Postfix Operators
Operator Function
++ X Prefix increment operator
-- X Prefix decrement operator
X++ Postfix increment operator
X -- Postfix decrement operator
• The execution of prefix operators occurs on the operand
prior to the evaluation of the whole expression
• The execution of postfix operators occurs after the
expression has been evaluated

9. Basic Relational Operators
Operator Function
< Less than operator
<= Less than or equal to operator
> Greater than operator
>= Greater than or equal to operator
• Those operators are used to compare integers, floating
points, and characters
• When the expression used with the relational operators is
true, the Boolean value of true is returned; otherwise, false
is returned

10. Equality Operators
Operator Function
== Equal to operator
!= Not equal to operator
• Relational operators that directly compare the equality of
primitives and object reference variables are considered
equality operators

11. Logical Operators
Operator Function
&& Logical AND to operator
|| Logical OR operator
• Logical (conditional) operators evaluate a pair of Boolean
operands. If both values of the operands have a value of
true, then a value of true is returned
• To return true with the AND operator both operands would
need to be true.
• To return true with the OR operator only one operand
needs to be true

12. Logical Negation Operator
Operator Function
! Logical negation operator
• It is also known as the inversion operator or Boolean invert
operator, and it returns the opposite of a Boolean value
• Expect to see the logical negation operator used in
conjunction with any method or expression that return a
Boolean value
• This operator cannot be used on a non-Boolean value

13. 2. Understanding Operator
Precedence
• Operator precedence is the order in which
operators will be evaluated when several operators
are included in an expression
• Operators with a higher precedence are evaluated
before operators with a lower precedence
• Operator precedence can be overridden using
parentheses
• When multiple sets of parentheses are present, the
innermost set is evaluated first

14. Precedence Order
• When two operators share an operand, the operator with
the higher precedence goes first. For example:
1 + 2 * 3 is treated as 1 + (2 * 3)
whereas
1 * 2 + 3 is treated as (1 * 2) + 3
since multiplication has a higher precedence than addition

15. Associativity
• When an expression has two operators with the same
precedence, the expression is evaluated according to its
associativity. For example:
x = y = z = 17 is treated as x = (y = (z = 17))
leaving all three variables with the value 17, since the =
operator has right-to-left associativity. On the other hand,
72 / 2 / 3 is treated as (72 / 2) / 3
since the / operator has left-to-right associativity.

16. Precedence and Associativity
of Java Operators
Operator Description Level Associativity
[] Access array element 1 Left to right
. Access object member
() Invoke a method
++ Post-increment
-- Post-decrement
++ Pre-increment 2 Right to left
-- Pre-decrement
+ Unary plus
- Unary minus
! Logical NOT
~ Bitwise NOT

17. Operator Description Level Associativity
() Cast 3 Right to left
new Object creation
* Multiplicative 4 Left to right
/
%
+ - Additive 5 Left to right
+ String concatenation
<< >> Shift 6 Left to right
>>>
< <= Relational type comparison 7 Left to right
> >=
== Equality 8 Left to right
!=
& Bitwise AND 9 Left to right
^ Bitwise XOR 10 Left to right

18. Operator Description Level Associativity
| Bitwise OR 11 Left to right
&& Conditional AND 12 Left to right
|| Conditional OR 13 Left to right
?: Conditional 14 Right to left
= += -= Assignment 15 Right to left
*= /= %=
&= ^= |=
<<= >>= >>>=

19. 4. Programming with
Java Strings
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