Basic Java 7

Basic Java 7

Java Operators

Java provides a rich set of operators enviroment. Java operators can be devided into following categories.

• Arithmetic operators.

• Relation operators.

• Logical operators.

• Bitwise operators.

• Assignment operators.

• Conditional operators.

• Misc operators.

1) Arithmetic operators

Arithmetic operators are used in mathematical expression in the same way that are used in algebra.

Operator	Description
+	adds two operands
-	subtract second operands from first
*	multiply two operand
/	divide numerator by denumerator
%	remainder of division
++	Increment operator increases integer value by one
--	Decrement operator decreases integer value by one

 

2) Relation operators

The following table shows all relation operators supported by Java.

Operator	Description
==	Check if two operand are equal
!=	Check if two operand are not equal.
>	Check if operand on the left is greater than operand on the right
<	Check operand on the left is smaller than
>=	Check left operand is greater than or equal to right operand
<=	Check if operand on left is smaller than or equal to right operand

3) Logical operators

Java supports following 3 logical operator. Suppose a=1 and b=0.

Operator	Description	Example
&&	Logical AND	&&
||	Logical OR	(a || b) is true
!	Logical NOT	(!a) is false

 

4) Bitwise operators

Java defines several bitwise operators that can be applied to the integer types long, int, short, char and byte.

Operator	Description
&	Bitwise AND
|	Bitwise OR
^	Bitwise exclusive OR
<<	left shift
>>	right shift

Now lets see truth table for bitwise &, | and ^

a	b	a & b	a | b	a ^ b
0	0	0	0	0
0	1	0	1	1
1	0	0	1	1
1	1	1	1	0

The bitwise shift operators shifts the bit value. The left operand specifies the value to be shifted and the right operand specifies the number of positions that the bits in the value are to be shifted. Both operands have the same precedence.

Example.

a = 0001000
b= 2
a << b= 0100000
a >> b= 0000010

5) Assignment operators

Assignment operator supported by Java are as follows.

Operator	Description	Example
=	assigns values from right side operands to left side operand	a=b
+=	adds right operand to the left operand and assign the result to left	a+=b is same as a=a+b
-=	subtracts right operand from the left operand and assign the result to left operand	a-=b is same as a=a-b
*=	mutiply left operand with the right operand and assign the result to left operand	a*=b is same as a=a*b
/=	divides left operand with the right operand and assign the result to left operand	a/=b is same as a=a/b
%=	calculate modulus using two operands and assign the result to left operand	a%=b is same as a=a%b

 

Misc operators

There are few other operator supported by java language.

6) Conditional operators

It is also known as ternary operator and used to evaluate Boolean expression.

epr1 ? expr2 : expr3

If epr1Condition is true? Then value expr2 : Otherwise value expr3.

7) instanceOf operators

This operator is used for object reference variables.
The operator checks whether the object is of particular type (class type or interface type).

About Java programs, it is very important to keep in mind the following points:

 

Precedence of Operators

Operators with the highest precedence appear at the top of the table, those with the lowest appear at the bottom. Within an expression, higher precedence operators will be evaluated first.

Operators	Precedence
postfix	expr++ expr--
unary	++expr --expr +expr -expr ~ !
multiplicative	* / %
additive	+ -
shift	<< >> >>>
relational	< > <= >= instanceof
equality	==  !=
bitwise AND	&
bitwise exclusive OR	^
bitwise inclusive OR	|
logical AND	&&
logical OR	||
ternary ? :	? :
assignment	= += -= *= /= %= &= ^= |= <<= >>= >>>=