2. Operators

2. Operators
	Chapter 3. The Java Language

Operators perform some function on either one or two operands.

2.1. Arithmetic Operators

Table 3.2. Arithmetic Operators

Operator	Use	Description
+	op1 + op2	Adds op1 and op2
-	op1 - op2	Subtracts op2 from op1
*	op1 * op2	Multiplies op1 and op2
/	op1 / op2	Divides op1 by op2
%	op1 % op2	Computes the remainder of dividing op1 by op2
+	+ op	Indicates a positive value
-	- op	Arithmetically negates op
++	op ++	Increments op by 1; Eval before incrementing
++	++ op	Increments op by 1; Eval after incrementing
--	op --	Decrements op by 1; Eval before decrementing
--	-- op	Decrements op by 1; Eval after decrementing

	Caution
	The Java language extends the definition of the operator + to include string concatenation.

2.2. Relational Operators

Table 3.3. Relational Operators

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 to 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

2.3. Conditional Operators

Table 3.4. Conditional Operators

Operator	Use	Returns true if
&&	op1 && op2	op1 and op2 are both true
\|\|	op1 \|\| op2	op1 or op2 is true
!	! op	op is false

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2.4. Bitwise Operators

Table 3.5. Bitwise Operators

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)
&	op1 & op2	bitwise and
\|	op1 \| op2	bitwise or
^	op1 ^ op2	bitwise xor
~	~ op	bitwise complement

2.5. Assignment Operator

You use the assignment operator, =, to assign one value to another.

	Caution
	The assignment operator just changes the pointer of Reference variables.

The code:

StringBuffer car1 = new StringBuffer("Toyota");
StringBuffer car2 = new StringBuffer("Ford");

Results in the following memory structures:

Figure 3.2. Memory Structure: 2 pointers

If the Assignment operator is used:

car2 = car1;

The car2 variable is pointed to the same object as car1 variable:

Figure 3.3. Memory Structure: Same pointer

A common source of mistakes is to think that car2 holds a copy of the object in car1 and to change it not expecting this to affect the object held by car1.

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2.6. Short Cuts for the Assignment operator

Table 3.6. Short Cut for the Assignment 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

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1. Variables and Data Types		3. Expressions and Control Flow Statements