Boolean vs boolean in Java

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There are discussions around Integer vs int in Java. The default value of the former is null while in the latter it's 0. How about Boolean vs boolean?

A variable in my application can have 0/1 values. I would like to use boolean/Boolean and prefer not to use int. Can I use Boolean/boolean instead?


Boolean vs boolean in Java, Yes you can use Boolean / boolean instead. First one is Object and second one is primitive type. On first one, you will get more methods which  Java: Boolean (class) vs boolean (primitive) A Boolean is a class, or a reference type, defined in the standard library. It stores a reference to an object containing a value (a "box"). A boolean on the other hand, is a primitive type and part of the language itself.


Boolean wraps the boolean primitive type. In JDK 5 and upwards, Oracle (or Sun before Oracle bought them) introduced autoboxing/unboxing, which essentially allows you to do this

boolean result = Boolean.TRUE;

or

Boolean result = true; 

Which essentially the compiler does,

Boolean result = Boolean.valueOf(true);

So, for your answer, it's YES.

JavaScript Boolean vs. boolean: Explained By Examples, In this tutorial, we will introduce you to the JavaScript Boolean object and show you the differences between Boolean object and boolean primitive type. The Boolean is also a wrapper object of the boolean primitive type. It means that when you use the Boolean constructor and pass in either true or false, you create a Boolean object. let b = new Boolean (false); To get the primitive value back, you call the valueOf() method of the Boolean object as follows: console.log(b.valueOf()); // false


I am a bit extending provided answers (since so far they concentrate on their "own"/artificial terminology focusing on programming a particular language instead of taking care of the bigger picture behind the scene of creating the programming languages, in general, i.e. when things like type-safety vs. memory considerations make the difference):

int is not boolean

Consider

    boolean bar = true;      
    System.out.printf("Bar is %b\n", bar);
    System.out.printf("Bar is %d\n", (bar)?1:0);
    int baz = 1;       
    System.out.printf("Baz is %d\n", baz);
    System.out.printf("Baz is %b\n", baz);

with output

    Bar is true
    Bar is 1
    Baz is 1
    Baz is true

Java code on 3rd line (bar)?1:0 illustrates that bar (boolean) cannot be implicitly converted (casted) into an int. I am bringing this up not to illustrate the details of implementation behind JVM, but to point out that in terms of low level considerations (as memory size) one does have to prefer values over type safety. Especially if that type safety is not truly/fully used as in boolean types where checks are done in form of

if value \in {0,1} then cast to boolean type, otherwise throw an exception.

All just to state that {0,1} < {-2^31, .. , 2^31 -1}. Seems like an overkill, right? Type safety is truly important in user defined types, not in implicit casting of primitives (although last are included in the first).

Bytes are not types or bits

Note that in memory your variable from range of {0,1} will still occupy at least a byte or a word (xbits depending on the size of the register) unless specially taken care of (e.g. packed nicely in memory - 8 "boolean" bits into 1 byte - back and forth).

By preferring type safety (as in putting/wrapping value into a box of a particular type) over extra value packing (e.g. using bit shifts or arithmetic), one does effectively chooses writing less code over gaining more memory. (On the other hand one can always define a custom user type which will facilitate all the conversion not worth than Boolean).

keyword vs. type

Finally, your question is about comparing keyword vs. type. I believe it is important to explain why or how exactly you will get performance by using/preferring keywords ("marked" as primitive) over types (normal composite user-definable classes using another keyword class) or in other words

boolean foo = true;

vs.

Boolean foo = true;

The first "thing" (type) can not be extended (subclassed) and not without a reason. Effectively Java terminology of primitive and wrapping classes can be simply translated into inline value (a LITERAL or a constant that gets directly substituted by compiler whenever it is possible to infer the substitution or if not - still fallback into wrapping the value).

Optimization is achieved due to trivial:

"Less runtime casting operations => more speed."

That is why when the actual type inference is done it may (still) end up in instantiating of wrapping class with all the type information if necessary (or converting/casting into such).

So, the difference between boolean and Boolean is exactly in Compilation and Runtime (a bit far going but almost as instanceof vs. getClass()).

Finally, autoboxing is slower than primitives

Note the fact that Java can do autoboxing is just a "syntactic sugar". It does not speed up anything, just allows you to write less code. That's it. Casting and wrapping into type information container is still performed. For performance reasons choose arithmetics which will always skip extra housekeeping of creating class instances with type information to implement type safety. Lack of type safety is the price you pay to gain performance. For code with boolean-valued expressions type safety (when you write less and hence implicit code) would be critical e.g. for if-then-else flow controls.

Boolean vs boolean in Java, Yes you can use Boolean/boolean instead. First one is Object and second one is primitive type. On first one, you will get more methods which  The answer is obviously no. Rest time between sets, movement quality, heart-rate, range of motion, time spent in eccentric vs concentric are all variables in the gym. All to say that, how you use the tool (time, in this case) is equally, if not more, important than the tool itself.


You can use the Boolean constants - Boolean.TRUE and Boolean.FALSE instead of 0 and 1. You can create your variable as of type boolean if primitive is what you are after. This way you won't have to create new Boolean objects.

Java.lang.Boolean Class in Java, TRUE or if it is false, then this method returns Boolean.FALSE. The other variant of this method is discussed next. Syntax : public static boolean valueOf(boolean b​)  boolean is a java primitive type. It only accepts true or false (which are declared constants in java). Boolean is a Serializable wrapper of boolean primitive type. From the JDK. The Boolean class wraps a value of the primitive type boolean in an object. An object of type Boolean contains a single field whose type is boolean.


Basically boolean represent a primitive data type where Boolean represent a reference data type. this story is started when Java want to become purely object oriented it's provided wrapper class concept to over come to use of primitive data type.

boolean b1;
Boolean b2;

b1 and b2 are not same.

Why is Java boolean primitive type name not 'bool'?, bool vs Boolean to use an established shorter name for primitive type? or. integer vs Integer to keep type names consistent? I think C++ had decided to use bool  #javascript #programming. How to create / publish / deploy / host an ASP.NET Core app on Debian Linux with Apache - Duration: 26:53. Vagelis Prokopiou 2,256 views


Boolean Vs boolean (Beginning Java forum at Coderanch), Hi Guys, Can any one post me a simple eg code to illustrate the diffrence between Boolean and bollean. That is object and prmitive date type. For this, Java has a boolean data type, which can take the values true or false. Boolean Values A boolean type is declared with the boolean keyword and can only take the values true or false :


What is the difference between boolean and object in Java?, Java has a primitive type, called boolean, for logical values. It can have only one of two possible values, true or false. But Boolean is a very thin wrapper around  The Boolean class wraps a value of the primitive type boolean in an object. An object of type Boolean contains a single field whose type is boolean.


Boolean (Java Platform SE 8 ), The Boolean object corresponding to the primitive value false . Returns the result of applying the logical OR operator to the specified boolean operands. Not so in Java. In Java, you can’t convert between an integer type and a boolean type. A Boolean expression is a Java expression that, when evaluated, returns a Boolean value: true or false. Boolean expressions are used in conditional statements, such as if, while, and switch.