Why boolean in Java takes only true or false Why not 1 or 0 also

Question

Is there any reason why Java booleans take only true or false why not 1 or 0 also

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Even though there is a bool  short for boolean  data type in C    But in C    any nonzero value is a true value including negative numbers  A 0  zero  is treated as false  Where as in JAVA there is a separate data type boolean for true and false

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Java  unlike languages like C and C    treats boolean as a completely separate data type which has 2 distinct values  true and false   The values 1 and 0 are of type int and are not implicitly convertible to boolean

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Being specific about this keeps you away from the whole TRUE in VB is -1 and in other langauges true is just NON ZERO  Keeping the boolean field as true or false keeps java outside of this argument

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Because booleans have two values  true or false   Note that these are not strings  but actual boolean literals   1 and 0 are integers  and there is no reason to confuse things by making them  alternative true  and  alternative false   or the other way round for those used to Unix exit codes     With strong typing in Java there should only ever be exactly two primitive boolean values   EDIT  Note that you can easily write a conversion function if you want   public static boolean intToBool int input       if  input  lt  0    input  gt  1             throw new IllegalArgumentException  input must be 0 or 1                Note we designate 1 as true and 0 as false though some may disagree    return input    1      Though I wouldn t recommend this   Note how you cannot guarantee that an int variable really is 0 or 1  and there s no 100  obvious semantics of what one means true   On the other hand  a boolean variable is always either true or false and it s obvious which one means true   -   So instead of the conversion function  get used to using boolean variables for everything that represents a true false concept   If you must use some kind of primitive text string  e g  for storing in a flat file    true  and  false  are much clearer in their meaning  and can be immediately turned into a boolean by the library method Boolean valueOf

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One thing that other answers haven t pointed out is that one advantage of not treating integers as truth values is that it avoids this C   C   bug syndrome   int i   0  if  i   1        print  the sky is falling  n         In C   C    the mistaken use of   rather than    causes the condition to unexpectedly evaluate to  true  and update i as an accidental side-effect   In Java  that is a compilation error  because the value of the assigment i   1 has type int and a boolean is required at that point   The only case where you d get into trouble in Java is if you write lame code like this   boolean ok   false  if  ok   true        bug and lame style     print  the sky is falling  n            which anyone with an ounce of  good taste  would write as      boolean ok   false  if  ok        print  the sky is falling  n

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On a related note  the java compiler uses int to represent boolean since JVM has a limited support for the boolean type See Section 3 3 4 The boolean type    In JVM  the integer zero represents false  and any non-zero integer represents true  Source   Inside Java Virtual Machine by Bill Venners

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In c and C   there is no data type called BOOLEAN  Thats why it uses 1 and 0 as true false value  and in JAVA 1 and 0 are count as an INTEGER type so it produces error in java  And java have its own boolean values true and false with boolean data type    happy programming

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Because the people who created Java wanted boolean to mean unambiguously true or false  not 1 or 0   There s no consensus among languages about how 1 and 0 convert to booleans  C uses any nonzero value to mean true and 0 to mean false  but some UNIX shells do the opposite  Using ints weakens type-checking  because the compiler can t guard against cases where the int value passed in isn t something that should be used in a boolean context

[java] Why boolean in Java takes only true or false? Why not 1 or 0 also?

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