Summary of Operators

This section offers summaries of the operators in the Java progamming language. This section has these subsections:

• Summary of Arithmetic Operators
• Summary of Relational and Conditional Operators
• Summary of Shift and Logical Operators
• Summary of Assignment Operators
• Summary of Other Operators
• Summary of Operator Precedence

The following table lists the basic arithmetic operators provided by the Java programming language. Except for +, which is also used to concatenate strings, these operators can be used only on numeric values.

Operator	Use	Description
+	op1 + op2	Adds op1 and op2
-	op1 - op2	Subtracts op2 from op1
*	op1 * op2	Multiplies op1 by op2
/	op1 / op2	Divides op1 by op2
%	op1 % op2	Computes the remainder of dividing op1 by op2

These short cut operators increment or decrement a number by one.

Operator	Use	Description
++	op++	Increments op by 1; evaluates to the value of op before it was incremented
++	++op	Increments op by 1; evaluates to the value of op after it was incremented
--	op--	Decrements op by 1; evaluates to the value of op before it was decremented
--	--op	Decrements op by 1; evaluates to the value of op after it was decremented

Here are the Java programming language's other arithmetic operators.

Operator	Use	Description
+	+op	Promotes op to int if it's a byte, short, or char
-	-op	Arithmetically negates op

Use these relational operators to determine the relationship between two values.

Operator	Use	Returns true if
>	op1 > op2	op1 is greater than op2
>=	op1 >= op2	op1 is greater than or equal to op2
<	op1 < op2	op1 is less than op2
<=	op1 <= op2	op1 is less than or equal to op2
==	op1 == op2	op1 and op2 are equal
!=	op1 != op2	op1 and op2 are not equal

You can use the following conditional operators to form multi-part decisions.

Operator	Use	Returns true if
&&	op1 && op2	op1 and op2 are both true, conditionally evaluates op2
||	op1 || op2	either op1 or op2 is true, conditionally evaluates op2
!	! op	op is false
&	op1 & op2	op1 and op2 are both true, always evaluates op1 and op2
|	op1 | op2	either op1 or op2 is true, always evaluates op1 and op2
^	op1 ^ op2	if op1 and op2 are different--that is if one or the other of the operands is true but not both

Each shift operator shifts the bits of the left-hand operand over by the number of positions indicated by the right-hand operand. The shift occurs in the direction indicated by the operator itself.

Operator	Use	Operation
>>	op1 >> op2	shift bits of op1 right by distance op2
<<	op1 << op2	shift bits of op1 left by distance op2
>>>	op1 >>> op2	shift bits of op1 right by distance op2 (unsigned)

These operators perform logical functions on their operands.

Operator	Use	Operation
&	op1 & op2	bitwise and
|	op1 | op2	bitwise or
^	op1 ^ op2	bitwise xor
~	~op2	bitwise complement

The basic assignment operator looks as follows and assigns the value of op2 to op1.

op1 = op2;

In addition to the basic assignment operation, the Java programming language defines these short cut assigment operators that perform an operation and an assignment using one operator.

Operator	Use	Equivalent to
+=	op1 += op2	op1 = op1 + op2
-=	op1 -= op2	op1 = op1 - op2
*=	op1 *= op2	op1 = op1 * op2
/=	op1 /= op2	op1 = op1 / op2
%=	op1 %= op2	op1 = op1 % op2
&=	op1 &= op2	op1 = op1 & op2
|=	op1 |= op2	op1 = op1 | op2
^=	op1 ^= op2	op1 = op1 ^ op2
<<=	op1 <<= op2	op1 = op1 << op2
>>=	op1 >>= op2	op1 = op1 >> op2
>>>=	op1 >>>= op2	op1 = op1 >>> op2

The Java programming language also supports these operators.

Operator	Use	Description
?:	op1 ? op2 : op3	If op1 is true, returns op2. Otherwise, returns op3.
[]	type []	Declares an array of unknown length, which contains type elements.
[]	type[ op2 ]	Creates and array with op1 elements. Must be used with the new operator.
[]	op1[ op2 ]	Accesses the element at op2 index within the array op1. Indices begin at 0 and extend through the length of the array minus one.
.	op1.op2	Is a reference to the op2 member of op1.
()	op1(params)	Declares or calls the method named op1 with the specified parameters. The list of parameters can be an empty list. The list is comma-separated.
(type)	(type) op1	Casts (converts) op1 to type. An exception will be thrown if the type of op1 is incompatible with type.
new	new op1	Creates a new object or array. op1 is either a call to a constructor, or an array specification.
instanceof	op1 instanceof op2	Returns true if op1 is an instance of op2

The following table shows the precedence assigned to Java's operators. The operators in this table are listed in precedence order: the higher in the table an operator appears, the higher its precedence. Operators with higher precedence are evaluated before operators with a relatively lower precedence. Operators on the same line have equal precedence.

postfix operators	[] . (params) expr++ expr--
unary operators	++expr --expr +expr -expr ~ !
creation or cast	new (type)expr
multiplicative	* / %
additive	+ -
shift	<< >> >>>
relational	< > <= >= instanceof
equality	== !=
bitwise AND	&
bitwise exclusive OR	^
bitwise inclusive OR	|
logical AND	&&
logical OR	||
conditional	? :
assignment	= += -= *= /= %= &= ^= |= <<= >>= >>>=