What is default boolean value in java

Boolean in java

Java boolean
A boolean in java is a primitive data type with only two possible values: true or false . This article will explain what is a boolean, how to use boolean in java, its default value and boolean array with example programs. Boolean values are most commonly used in
1. if statements where the condition should result in true or false .
2. Java ternary operator where the first operand or the expression should return a boolean.
3. Comparison of values with each other using logical( && or || ) or equality( == ) operators always results in a boolean value.
A variable of type boolean is declared with boolean keyword.

boolean example
Below is an example program which declares and prints the values of boolean variables.

public class BooleanDeclaration < public static void main(String[] a) < // declare variables boolean start = true; boolean stop = false; // print variables System.out.println("Start value is: " + start); System.out.println("Stop value is: " + stop); >>

Boolean expression
An expression which returns a boolean value is a boolean expression in java. As stated earlier, comparisons performed with logical or equality operator always return a boolean value.
Below is an example program which shows the usage of a boolean expression to compare two integers with if statement

public class BooleanDeclaration < public static void main(String[] a) < // declare variables int numOne = 10; int numTwo = 20; // compare variables if(numOne == numTwo) < System.out.println("Values are equal"); >else < System.out.println("Values are not equal"); >> >

Java boolean method
A method in java may also return a boolean value. Return type of such method must be boolean . Example program is

public class BooleanDeclaration < public static void main(String[] a) < // declare variables int numOne = 10; int numTwo = 20; if(compareNumbers(numOne, numTwo))< System.out.println("Values are equal"); >else < System.out.println("Values are not equal"); >> // boolean method static boolean compareNumbers(int numOne, int numTwo) < // compare variables if(numOne == numTwo) < return true; >else < return false; >> >

A boolean method should return either true or false value.
As already stated, comparison expression results in a boolean value. Thus, the method in above example can be shortened by directly returning result of boolean expression as shown below.

static boolean compareNumbers(int numOne, int numTwo) < // compare variables return numOne == numTwo; >

• To create a wrapper object from primitive value, use its valueOf() method which accepts a primitive value as argument. valueOf() is a static method, so you don’t need an object to invoke it.
• To get primitive value from a wrapper object, use its booleanValue() method.
• To convert a boolean primitive to String, call toString() method on wrapper object.
• To compare two boolean wrappers, use its equals() method. It compares the value of the underlying primitives and returns true if they are same.

public class BooleanToString < public static void main(String[] args) < // declare a boolean primitive boolean primitive = true; // convert to wrapper object Boolean wrapper = Boolean.valueOf(primitive); // get its boolean value System.out.println(wrapper.booleanValue()); // convert boolean to string String boolString = wrapper.toString(); System.out.println("Boolean to string is: " + boolString); // create another wrapper Boolean wrapperTwo = Boolean.valueOf(false); // compare wrapper objects if (wrapper.equals(wrapperTwo)) < System.out.println("Primitive values are same"); >else < System.out.println("Primitive values are not same"); >> >

true
Boolean to string is: true
Primitive values are not same

Null handling
You can not initialize a boolean primitive to null, but a boolean wrapper can be initialized to null , which means that you can compare it to null as shown below.

Boolean b = null; if(b == null)

Further, if a null is supplied to valueOf() method while creating a wrapper object, then the underlying primitive value is false . Example,

Boolean wrapper = Boolean.valueOf(null); if(wrapper.booleanValue()) < System.out.println("boolean is true"); >else

Boolean arrays
An array in java is a collection of values of same data type. You can create an array of boolean values. Syntax is

boolean[] var = new boolean[size];

Providing a size is mandatory.
Elements of the array are indexed starting from 0, which means that first element is at index 0, second is at index 1 and so on.
Default values of elements of a boolean array are false .

There is another way of initializing a boolean array where you can provide initial values as shown below

This method is suitable when the size of array is small. Example program is given below

public class DatamigrationApplication < public static void main(String[] args) throws IOException < boolean[] arr = new boolean[5]; for (boolean bool : arr) < System.out.println("Default value is: "+bool); >> >

Default value is: false
Default value is: false
Default value is: false
Default value is: false
Default value is: false

All the elements are initialized to false by default. If the array is of Boolean wrapper objects, then the elements are initialized to null by default.
This is because the elements of wrapper array are objects and objects in java are initialized to null by default.

We can assign value to an array element using its index and assignment operator as shown below.
// assign element at third place

That is all on boolean values in java. Hope the article was helpful.

Источник

Default boolean value in java

In this article, we will learn about the default value of a boolean keyword in java. This primitive data type can have only two possible values i.e. true and false. Generally, this data type is used in java programming to check or handle the true/false conditional check.

So don’t waste your time and continue reading this article thoroughly to clear all your doubts related to boolean data type default value.

What is mean by the default value of a variable?

A default value is an initial value assigned to a variable when it is not initialized in the program. Like default value for the int data type is 0, if you don’t initialize it.

What is default boolean value in java?

The default boolean value in java is false

In java programming false is stored as 0 and true is stored as 1 in the database.

How to check default boolean value in java?

In the below example we have printed the value of a boolean variable that is not initialized. So t will print the default value assigned to it.

package com.technolads; public class Technolads_Test < //Declare boolean variable static boolean testVariable; public static void main(String[] args) < System.out.println("Boolean variable default value is: " + testVariable); >>

Following is the output of the above program.

Boolean variable default value is: false

Conclusion:

In this article, we studied what is the default boolean value in java and how you can check.

We hope this article was informative and you got a clear idea about the boolean data type. If you need further clarification on any of the above points then please do mention it in the comment section or you can reach out to us using Contact Form.

Frequently asked questions:

What is the difference between boolean and Boolean in java?

boolean is a primitive data type and its default value is false.

Boolean is a wrapper class and the default value of its object is null.

How to set an initial value for a boolean variable in java?

You can set the initial value as true of a boolean variable as shown below:

boolean testBooleanVariable = true;

What is the size of a boolean data type?

The precise size of a boolean variable is not mentioned in the java specification. It depends on the Java Virtual Machine on which the java application is running.

Источник

Java boolean default value

In this post, we will see what is default value of boolean and Boolean in java.

💡 Did you know?

The Default value of boolean is false and wrapper class Boolean is null .

Here is the example to demonstrate the same.

As you can see default value of boolean is false and Boolean is null .

That’s all about Java boolean default value.

Was this post helpful?

Share this

Related Posts

Author

Related Posts

Privacy Policy

Table of ContentsWhat information do we collect?How do we use your information?Information DisclosureThird-party cookiesChangesContacting Us What information do we collect? On this website, you are required to : enter your email address to get the latest updates from this blog directly into your email box for free enter your name, email, and the website you […]

Manage C Sharp Homework Assignment at Ease Online

Table of ContentsC Sharp Homework Help: Use the Service and Get Your BenefitsC Sharp Assignment Help: Sound Guarantees for the CustomersTop-Notch Authentic ContentPrivacy24/7 SupportPlace Your Order and Get the Task Down at Ease In this post, we will see how to manage C sharp homework assignment online. Who can do my c# assignment fast? The […]

How is java distributed

Table of ContentsIntroductionFeatures of JavaDistributed System and Programing LanguageJava is a distributed language.Extended LibrariesIntegration of New TechnologyJVM (Java Virtual Machine)Networking SupportConclusion Introduction Java is considered to be the most secure platform and programming language. Java was developed in 1995 by Sun Microsystems. It is the most commonly used language among developers, which is easy to […]

How to view HTTP headers in Google Chrome?

In this post, we will see how to view HTTP headers in Google Chrome. Here are the steps to view HTTP headers in google chrome. Right-click on the webpage and select Inspect. Click on Network tab. Pick any HTTP request from left panel and click on headers to view HTTP header. You will be able […]

Caesar Cipher in Java

Table of ContentsAlgorithmImplementationStep 1(Mapping Plaintext) :Step 2(Encrypting and Obtaining CipherText) :Step 3(Decrypting and Obtaining our original Text) : In this post, we will see about Caesar Cipher in Java. In cryptography, we used to study different algorithms or techniques to encrypt and decrypt a different sets of messages to gain confidentiality, integrity or say some […]

System.out.println in java

Table of ContentsWhat is System.out.println?Does System.out.println impact performance? In this post, we will see about System.out.println in java and how it works. Did you use system.out.println before? I think this is first statement every java developer compiles. It is generally called by the acronym «SOP». What is System.out.println? System.out.println is Java statement which prints argument […]

Источник

Default value of boolean and boolean array in Java

In this post, we will learn what is the default value of boolean and boolean array in Java.

In Java, the boolean keyword is used to declare the variable as a boolean type that can have only two values either true or false.

Default value of boolean in Java

The default value of primitive boolean is false whereas the Boolean object is null.

Java program to find the default value of boolean

public class DefaultBooleanValue< boolean primitiveBoolean; Boolean objectBoolean; public static void main(String args[]) < DefaultBooleanValue obj = new DefaultBooleanValue(); obj.printDefaultBooleanValues(); > public void printDefaultBooleanValues( ) < System.out.println("default value of primitive boolean is: "+ primitiveBoolean); System.out.println("default value of Boolean object is: "+ objectBoolean); > >

Output:
default value of primitive boolean is: false
default value of Boolean object is: null

From the above example, you can find that the default value of boolean is false and the Boolean object is null.

Default value of boolean array in Java

The boolean array can contain only boolean datatype values and the default value is false. Similarly, the boolean array of reference types has the default value of null.

The default value of the primitive boolean array is false whereas the Boolean object array is null.

Java program to find the default value of a boolean array

public class DefaultBooleanArrayValue < boolean[] primitiveBooleanArray = new boolean[3]; Boolean[] objectBooleanArray = new Boolean[3]; int length = primitiveBooleanArray.length; public static void main(String args[]) < DefaultBooleanArrayValue obj = new DefaultBooleanArrayValue(); obj.printDefaultBooleanValues(); > public void printDefaultBooleanValues( ) < for(int i=0 ; i < length; i++) < System.out.println("default value of primitive boolean array is: "+ primitiveBooleanArray[i]); System.out.println("default value of Boolean object array is: "+ objectBooleanArray[i]); > > >

Output:
default value of primitive boolean array is: false
default value of Boolean object array is: null
default value of primitive boolean array is: false
default value of Boolean object array is: null
default value of primitive boolean array is: false
default value of Boolean object array is: null

That’s all for today, please mention in the comments in case you have any questions related to default value of boolean and boolean array in Java.

About The Author

Subham Mittal has worked in Oracle for 3 years.
Enjoyed this post? Never miss out on future posts by subscribing JavaHungry

Источник