Boolean Wrapper Class in Java

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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.
In addition, this class provides many methods for converting a boolean to a String and a String to a boolean, as well as other constants and methods useful when dealing with a boolean.

Boolean class Constructors

  • Boolean(boolean value) - Allocates a Boolean object representing the value argument.
  • Boolean(String s) - Allocates a Boolean object representing the value true if the string argument is not null and is equal, ignoring case, to the string "true".

Example:
Boolean boolean1 = new Boolean(true);
Boolean boolean2 = new Boolean("boolean");

Boolean class Methods

The class diagram shows a list of APIs/Methods that Boolean class provides.
In this post, we will learn a few important methods of the Boolean wrapper class.

parseBoolean(String s)

Parses the string argument as a boolean. The boolean returned represents the value true if the string argument is not null and is equal, ignoring case, to the string "true".
Example:
private static void parseBoolean(){
  // parsing different Strings
 boolean b1 = Boolean.parseBoolean("True");
 boolean b2 = Boolean.parseBoolean("TruE");
 boolean b3 = Boolean.parseBoolean("False");
 boolean b4 = Boolean.parseBoolean("FALSE");
 boolean b5 = Boolean.parseBoolean("GeeksForGeeks");
  
 System.out.println(b1);
 System.out.println(b2);
 System.out.println(b3);
 System.out.println(b4);
 System.out.println(b5);
}

booleanValue()

Returns the value of this Boolean object as a boolean primitive.
Example:
private static void booleanValue(){
  // creating different Boolean objects
 Boolean b1 = new Boolean("True");
 Boolean b2 = new Boolean("False");
 Boolean b3 = new Boolean("GeeksForGeeks");
  
 // getting primitive boolean value
 boolean b4 = b1.booleanValue();
 boolean b5 = b2.booleanValue();
 boolean b6 = b3.booleanValue();
  
 System.out.println(b4);
 System.out.println(b5);
 System.out.println(b6);
}

valueOf(boolean b)

Returns a Boolean instance representing the specified boolean value. If the specified boolean value is true, this method returns Boolean.TRUE; if it is false, this method returns Boolean.FALSE.
Example:
private static void valueOf(){
 // creating boolean variable
 boolean b1 = true;
 boolean b2 = false;
  
 // getting Boolean objects from boolean variables
 Boolean b3 = Boolean.valueOf(b1);
 Boolean b4 = Boolean.valueOf(b2);
  
 System.out.println(b3);
 System.out.println(b4);
}

valueOf(String s)

Returns a Boolean with a value represented by the specified string. The Boolean returned represents a true value if the string argument is not null and is equal, ignoring case, to the string "true".
Example:
private static void valueOf1(){
  // creating boolean variable using different Strings
 Boolean b1 = Boolean.valueOf("true");
 Boolean b2 = Boolean.valueOf("TRue");
 Boolean b3 = Boolean.valueOf("False");
 Boolean b4 = Boolean.valueOf("GeeksForGeeks");
 Boolean b5 = Boolean.valueOf(null);
  
 System.out.println(b1);
 System.out.println(b2);
 System.out.println(b3);
 System.out.println(b4);
 System.out.println(b5);
}

toString(boolean b)

Returns a String object representing the specified boolean.
Example:
private static void toStringTest(){
  // creating boolean variable
 boolean b1 = true;
 boolean b2 = false;
  
 // getting String value of the primitives boolean
 String str1 = Boolean.toString(b1);
 String str2 = Boolean.toString(b2);
  
 System.out.println(str1);
 System.out.println(str2);
 
}

toString()

Returns a String object representing this Boolean's value.
Example:
private static void toStringTest1(){
  // creating different Boolean objects
 Boolean b1 = new Boolean("True");
 Boolean b2 = new Boolean("False");
 Boolean b3 = new Boolean("GeeksForGeeks");
 Boolean b4 = new Boolean(null);
 
  
 // getting String value of Boolean objects
 String str1 = b1.toString();
 String str2 = b2.toString();
 String str3 = b3.toString();
 String str4 = b4.toString();
  
 System.out.println(str1);
 System.out.println(str2);
 System.out.println(str3);
 System.out.println(str4);
}

hashCode()

Returns a hash code for this Boolean object.
Example:
private static void hashCodeTest(){
 // creating different Boolean objects
 Boolean b1 = new Boolean("True");
 Boolean b2 = new Boolean("False");
 Boolean b3 = new Boolean("TRue");
 Boolean b4 = new Boolean(null);
 
 System.out.println(b1.hashCode());
 System.out.println(b2.hashCode());
 System.out.println(b3.hashCode());
 System.out.println(b4.hashCode());
}

equals(Object obj)

Returns true if and only if the argument is not null and is a Boolean object that represents the same boolean value as this object.
Example:
private static void equalsTest(){
 // creating different Boolean objects
 Boolean b1 = new Boolean("True");
 Boolean b2 = new Boolean("False");
 Boolean b3 = new Boolean("TrUe");
 Boolean b4 = new Boolean(null);
  
 
 // checking equality of Boolean objects
 System.out.println(b1.equals(b2));
 System.out.println(b2.equals(b4));
 System.out.println(b1.equals(b3));
 System.out.println(b1.equals(b4));
}

compareTo(Boolean b)

Compares this Boolean instance with another.
Example:
private static void comparetoTest(){
 // creating different Boolean objects
 Boolean b1 = new Boolean("True");
 Boolean b2 = new Boolean("False");
 Boolean b3 = new Boolean("TRue");
 Boolean b4 = new Boolean(null);
 
 //comparing b1,b2,b3,b4
 System.out.println(b1.compareTo(b2));
 System.out.println(b1.compareTo(b3));
 System.out.println(b2.compareTo(b1));
 System.out.println(b1.compareTo(b4));
 System.out.println(b2.compareTo(b4));
  
 // The following statement throws NullPointerExcetion
 //  System.out.println(b1.compareTo(null));
}

compare(boolean x, boolean y)

Compares two boolean values. The value returned is identical to what would be returned by:Boolean.valueOf(x).compareTo(Boolean.valueOf(y))
Example:
private static void compareTest(){
 // creating boolean variable
 boolean b1 = true;
 boolean b2 = false;
 boolean b3 = true;
 boolean b4 = false;
  
 //comparing b1,b2,b3,b4
 System.out.println(Boolean.compare(b1, b2));
 System.out.println(Boolean.compare(b1, b3));
 System.out.println(Boolean.compare(b2, b1));
 System.out.println(Boolean.compare(b2, b4));
  
 // The following statement throws NullPointerExcetion
 //  System.out.println(Boolean.compare(b1, null));
}

Reference

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