Why do we usually use over What is the difference

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I m just wondering why we usually use logical OR    between two booleans not bitwise OR    though they are both working well   I mean  look at the following   if true    true      pass if true    false     pass if false   true      pass if false   false     no pass     if true     true      pass if true     false     pass if false    true      pass if false    false     no pass   Can we use   instead of     Same thing with  amp  and  amp  amp

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is a logical or and   is a bit-wise or

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a   b  evaluate b in any case  a    b  evaluate b only if a evaluates to false

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The only time you would use   or  amp  instead of    or  amp  amp  is when you have very simple boolean expressions and the cost of short cutting  i e  a branch  is greater than the time you save by not evaluating the later expressions   However  this is a micro-optimisation which rarely matters except in the most low level code

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bitwise or       logic or

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is the logical or operator while   is the bitwise or operator   boolean a   true  boolean b   false   if  a    b       int a   0x0001  a   a   0x0002

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bitwise or       logic or

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If you use the    and  amp  amp  forms  rather than the   and  amp  forms of these operators  Java will not bother to evaluate the right-hand operand alone   It s a matter of if you want to short-circuit the evaluation or not -- most of the time you want to   A good way to illustrate the benefits of short-circuiting would be to consider the following example   Boolean b   true  if b    foo timeConsumingCall           we entered without calling timeConsumingCall       Another benefit  as Jeremy and Peter mentioned  for short-circuiting is the null reference check    if string    null  amp  amp  string isEmpty            we check for string being null before calling isEmpty       more info

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Logical    and  amp  amp  check the right hand side only if necessary  The   and  amp  check both the sides everytime   For example   int i   12  if  i    10  amp  i  lt  9     It will check if i    10 and if i  lt  9       Rewrite it   int i   12  if  i    10  amp  amp  i  lt  9     It will check if i    10 and stop checking afterward because i    10       Another example   int i   12  if  i    12   i  gt  10     It will check if i    12 and it will check if i  gt  10       Rewrite it   int i   12  if  i    12    i  gt  10     It will check if i    12  it does  so it stops checking and executes what is in the if statement

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is the binary or operator     is the logic or operator

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Also notice a common pitfall  The non lazy operators have precedence over the lazy ones  so   boolean a  b  c  a    b  amp  amp  c    resolves to a     b  amp  amp  c  a   b  amp  amp  c    resolves to  a   b   amp  amp  c   Be careful when mixing them

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Take a look at   http   java sun com docs books tutorial java nutsandbolts operators html    is bitwise inclusive OR     is logical OR

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does not do short-circuit evaluation in boolean expressions     will stop evaluating if the first operand is true  but   won t   In addition    can be used to perform the bitwise-OR operation on byte short int long values     cannot

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In Addition to the fact that   is a bitwise-operator     is a short-circuit operator - when one element is false  it will not check the others    if something    someotherthing   if something   someotherthing    if something is TRUE     will not evaluate someotherthing  while   will do  If the variables in your if-statements are actually function calls  using    is possibly saving a lot of performance

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is the logical or operator while   is the bitwise or operator   boolean a   true  boolean b   false   if  a    b       int a   0x0001  a   a   0x0002

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usually I use when there is pre increment and post increment operator  Look at the following code   package ocjpPractice          author tithik        public class Ex1        public static void main String   args        int i 10      int j 9      int x 10      int y 9      if i  10     i gt j           System out println  it will print in first if              System out println  i is    i              if x  10     x gt y           System out println  it will print in second if               System out println  x is    x                   output      it will print in first if   i is  11   it will print in second if   x is  10   both if blocks are same but result is different  when there is    both the conditions will be evaluated  But if it is     it will not evaluate second condition as the first condition is already true

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does not do short-circuit evaluation in boolean expressions     will stop evaluating if the first operand is true  but   won t   In addition    can be used to perform the bitwise-OR operation on byte short int long values     cannot

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Non short-circuiting can be useful   Sometimes you want to make sure that two expressions evaluate   For example  say you have a method that removes an object from two separate lists   You might want to do something like this   class foo        ArrayList lt Bar gt  list1   new ArrayList lt Bar gt         ArrayList lt Bar gt  list2   new ArrayList lt Bar gt            Returns true if bar is removed from both lists  otherwise false      boolean removeBar Bar bar            return  list1 remove bar   amp  list2 remove bar              If your method instead used the conditional operand  it would fail to remove the object from the second list if the first list returned false     Fails to execute the second remove if the first returns false  boolean removeBar Bar bar        return  list1 remove bar   amp  amp  list2 remove bar        It s not amazingly useful  and  as with most programming tasks  you could achieve it with other means   But it is a use case for bitwise operands

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is a bitwise operator     is a logical operator   One will take two bits and or them   One will determine truth  this OR that  If this is true or that is true  then the answer is true   Oh  and dang people answer these questions fast

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Java operators    is bitwise or     is logical or

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In addition to short-circuiting  another thing to keep in mind is that doing a bitwise logic operation on values that can be other than 0 or 1 has a very different meaning than conditional logic   While it USUALLY is the same for   and     with  amp  and  amp  amp  you get very different results  e g  2  amp  4 is 0 false while 2  amp  amp  4 is 1 true    If the thing you re getting from a function is actually an error code and you re testing for non-0-ness  this can matter quite a lot   This isn t as much of an issue in Java where you have to explicitly typecast to boolean or compare with 0 or the like  but in other languages with similar syntax  C C   et al  it can be quite confusing   Also  note that  amp  and   can only apply to integer-type values  and not everything that can be equivalent to a boolean test   Again  in non-Java languages  there are quite a few things that can be used as a boolean with an implicit    0 comparison  pointers  floats  objects with an operator bool    etc   and bitwise operators are almost always nonsensical in those contexts

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The operators    and  amp  amp  are called conditional operators  while   and  amp  are called bitwise operators  They serve different purposes   Conditional operators works only with expressions that statically evaluate to boolean on both left- and right-hand sides   Bitwise operators works with any numeric operands   If you want to perform a logical comparison  you should use conditional operators  since you will add some kind of type safety to your code

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is a logical or and   is a bit-wise or

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Java operators    is bitwise or     is logical or

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1   expression1   expression2     operator will evaluate expression2 irrespective of whether the result of expression1 is true or false   Example   class Or        public static void main String   args                 boolean b true           if  b   test                static boolean test                 System out println  No short circuit             return false            2   expression1    expression2      operator will not evaluate expression2 if expression1 is true   Example   class Or        public static void main String   args                 boolean b true           if  b    test                          System out println  short circuit                          static boolean test                 System out println  No short circuit             return false

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In Addition to the fact that   is a bitwise-operator     is a short-circuit operator - when one element is false  it will not check the others    if something    someotherthing   if something   someotherthing    if something is TRUE     will not evaluate someotherthing  while   will do  If the variables in your if-statements are actually function calls  using    is possibly saving a lot of performance

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A side note  Java has    but not an      An example of when you must use    is when the first expression is a test to see if the second expression would blow up  e g  Using a single   in hte following case could result in an NPE   public static boolean isNotSet String text       return text    null    text length      0

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is the binary or operator     is the logic or operator

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returns a boolean value by OR ing two values  Thats why its known as a LOGICAL or   IE   if  A    B     Would return true if either A or B is true  or false if they are both false     is an operator that performs a bitwise operation on two values  To better understand bitwise operations  you can read here   http   en wikipedia org wiki Bitwise operation

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There are many use cases suggesting why should you go for    rather than     Some use cases have to use   operator to check all the conditions   For example  if you want to check form validation and you want to show the user all the invalid fields with error texts rather than just a first invalid field      operator would be       if checkIfEmpty nameField     checkIfEmpty phoneField     checkIfEmpty emailField              invalid form with one or more empty fields          private boolean checkIfEmpty Widget field          if field isEmpty              field setErrorMessage  Should not be empty             return true                return false         So with above snippet  if user submits the form with ALL empty fields  ONLY nameField would be shown with error message  But  if you change it to      if checkIfEmpty nameField    checkIfEmpty phoneField    checkIfEmpty emailField              invalid form with one or more empty fields        It will show proper error message on the each field irrespective of true conditions

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The other answers have done a good job of covering the functional difference between the operators  but the answers could apply to just about every single C-derived language in existence today  The question is tagged with java  and so I will endeavor to answer specifically and technically for the Java language    amp  and   can be either Integer Bitwise Operators  or Boolean Logical Operators  The syntax for the Bitwise and Logical Operators    15 22  is   AndExpression    EqualityExpression    AndExpression  amp  EqualityExpression  ExclusiveOrExpression    AndExpression    ExclusiveOrExpression   AndExpression  InclusiveOrExpression    ExclusiveOrExpression    InclusiveOrExpression   ExclusiveOrExpression   The syntax for EqualityExpression is defined in   15 21  which requires RelationalExpression defined in   15 20  which in turn requires ShiftExpression and ReferenceType defined in   15 19 and   4 3  respectively  ShiftExpression requires AdditiveExpression defined in   15 18  which continues to drill down   defining the basic arithmetic  unary operators  etc  ReferenceType drills down into all the various ways to represent a type   While ReferenceType does not include the primitive types  the definition of primitive types is ultimately required  as they may be the dimension type for an array  which is a ReferenceType    The Bitwise and Logical Operators have the following properties         These operators have different precedence  with  amp  having the highest precedence and   the lowest precedence    Each of these operators is syntactically left-associative  each groups left-to-right     Each operator is commutative if the operand expressions have no side effects    Each operator is associative    The bitwise and logical operators may be used to compare two operands of numeric type or two operands of type boolean  All other cases result in a compile-time error       The distinction between whether the operator serves as a bitwise operator or a logical operator depends on whether the operands are  convertible to a primitive integral type     4 2  or if they are of types boolean or Boolean    5 1 8    If the operands are integral types  binary numeric promotion    5 6 2  is performed on both operands  leaving them both as either longs or ints for the operation  The type of the operation will be the type of the  promoted  operands  At that point   amp  will be bitwise AND    will be bitwise exclusive OR  and   will be bitwise inclusive OR     15 22 1   If the operands are boolean or Boolean  the operands will be subject to unboxing conversion if necessary    5 1 8   and the type of the operation will be boolean   amp  will result in true if both operands are true    will result in true if both operands are different  and   will result in true if either operand is true     15 22 2   In contrast   amp  amp  is the  Conditional-And Operator     15 23  and    is the  Conditional-Or Operator     15 24   Their syntax is defined as   ConditionalAndExpression    InclusiveOrExpression    ConditionalAndExpression  amp  amp  InclusiveOrExpression  ConditionalOrExpression    ConditionalAndExpression    ConditionalOrExpression    ConditionalAndExpression    amp  amp  is like  amp   except that it only evaluates the right operand if the left operand is true     is like    except that it only evaluates the right operand if the left operand is false   Conditional-And has the following properties         The conditional-and operator is syntactically left-associative  it groups left-to-right     The conditional-and operator is fully associative with respect to both side effects and result value  That is  for any expressions a  b  and c  evaluation of the expression   a   amp  amp   b    amp  amp   c  produces the same result  with the same side effects occurring in the same order  as evaluation of the expression  a   amp  amp    b   amp  amp   c      Each operand of the conditional-and operator must be of type boolean or Boolean  or a compile-time error occurs    The type of a conditional-and expression is always boolean    At run time  the left-hand operand expression is evaluated first  if the result has type Boolean  it is subjected to unboxing conversion    5 1 8     If the resulting value is false  the value of the conditional-and expression is false and the right-hand operand expression is not evaluated    If the value of the left-hand operand is true  then the right-hand expression is evaluated  if the result has type Boolean  it is subjected to unboxing conversion    5 1 8   The resulting value becomes the value of the conditional-and expression    Thus   amp  amp  computes the same result as  amp  on boolean operands  It differs only in that the right-hand operand expression is evaluated conditionally rather than always       Conditional-Or has the following properties         The conditional-or operator is syntactically left-associative  it groups left-to-right     The conditional-or operator is fully associative with respect to both side effects and result value  That is  for any expressions a  b  and c  evaluation of the expression   a      b       c  produces the same result  with the same side effects occurring in the same order  as evaluation of the expression  a       b      c      Each operand of the conditional-or operator must be of type boolean or Boolean  or a compile-time error occurs    The type of a conditional-or expression is always boolean    At run time  the left-hand operand expression is evaluated first  if the result has type Boolean  it is subjected to unboxing conversion    5 1 8     If the resulting value is true  the value of the conditional-or expression is true and the right-hand operand expression is not evaluated    If the value of the left-hand operand is false  then the right-hand expression is evaluated  if the result has type Boolean  it is subjected to unboxing conversion    5 1 8   The resulting value becomes the value of the conditional-or expression    Thus     computes the same result as   on boolean or Boolean operands  It differs only in that the right-hand operand expression is evaluated conditionally rather than always       In short  as  JohnMeagher has repeatedly pointed out in the comments   amp  and   are  in fact  non-short-circuiting boolean operators in the specific case of the operands being either boolean or Boolean  With good practices  ie  no secondary effects   this is a minor difference  When the operands aren t booleans or Booleans  however  the operators behave very differently  bitwise and logical operations simply don t compare well at the high level of Java programming

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is a bitwise operator     is a logical operator   One will take two bits and or them   One will determine truth  this OR that  If this is true or that is true  then the answer is true   Oh  and dang people answer these questions fast

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The basic difference between them is that   first converts the values to binary then performs the bit wise or operation  Meanwhile     does not convert the data into binary and just performs the or expression on it s original state   int two   -2  int four   -4  result   two   four     bitwise OR example  System out println Integer toBinaryString two    System out println Integer toBinaryString four    System out println Integer toBinaryString result     Output  11111111111111111111111111111110 11111111111111111111111111111100 11111111111111111111111111111110   Read more  http   javarevisited blogspot com 2015 01 difference-between-bitwsie-and-logical html ixzz45PCxdQhk

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After carefully reading this topic is still unclear to me if using   as a logical operator is conform to Java pattern practices    I recently modified code in a pull request addressing a comment where   if function1     function2               had to be changed to   boolean isChanged   function1    isChanged    function2    if  isChanged             What is the actual accepted version       Java documentation is not mentioning   as a logical non-shortcircuiting OR operator    Not interested in a vote but more in finding out the standard   Both code versions are compiling and working as expected

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Take a look at   http   java sun com docs books tutorial java nutsandbolts operators html    is bitwise inclusive OR     is logical OR

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When I had this question I created test code to get an idea about this   public class HelloWorld      public static boolean bool          System out println  Bool          return true           public static void main String   args         boolean a   true       boolean b   false        if a  bool                   System out println  If condition executed                 else           System out println  Else condition executed                   In this case  we only change left side value of if condition adding a or b         Scenario   when left side true  if a  bool       output  If condition executed         Scenario   when left side false  if b  bool       Output-     Bool If condition executed   Conclusion of    When use     right side only check when the left side is false        Scenario   when left side true  if a bool       Output-     Bool If condition executed        Scenario   when left side false  if b bool       Output-     Bool If condition executed   Conclusion of   When use    check both left and right side

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So just to build on the other answers with an example  short-circuiting is crucial in the following defensive checks   if  foo    null    foo isClosed          return     if  bar    null  amp  amp  bar isBlue          foo doSomething        Using   and  amp  instead could result in a NullPointerException being thrown here

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One main difference is that    and  amp  amp  exhibit  short-circuiting   so the RHS will only be evaluated if needed    For e g    if  a    b        path1      else       path2       Above if a is true then b will not be tested and path1 is executed  If   was used then both sides would be evaluated even if  a  is true    See Here and here  for a little more information   Hope this helps

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returns a boolean value by OR ing two values  Thats why its known as a LOGICAL or   IE   if  A    B     Would return true if either A or B is true  or false if they are both false     is an operator that performs a bitwise operation on two values  To better understand bitwise operations  you can read here   http   en wikipedia org wiki Bitwise operation

[java] Why do we usually use || over |? What is the difference?

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