Boolean

AI-generated Key Takeaways

• The Boolean class in Java is a wrapper for the primitive boolean type, providing an object representation for boolean values.

• It offers methods for converting between boolean and String representations, and for performing logical operations.

• Boolean objects can be created using constructors or the static factory method valueOf, with valueOf being generally preferred for performance reasons.

• Key constants include TRUE, FALSE, and TYPE, representing the boolean values and the class object for the primitive type.

• The class provides methods like booleanValue, compare, compareTo, equals, hashCode, and others for working with boolean values in object form.

public final class Boolean extends Object
implements Serializable Comparable<Boolean>

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.

Field Summary

public static final Boolean	FALSE	The Boolean object corresponding to the primitive value false.
public static final Boolean	TRUE	The Boolean object corresponding to the primitive value true.
public static final Class<Boolean>	TYPE	The Class object representing the primitive type boolean.

Public Constructor Summary

	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".

Public Method Summary

boolean	booleanValue() Returns the value of this Boolean object as a boolean primitive.
static int	compare(boolean x, boolean y) Compares two boolean values.
int	compareTo(Boolean b) Compares this Boolean instance with another.
boolean	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.
static boolean	getBoolean(String name) Returns true if and only if the system property named by the argument exists and is equal to the string "true".
int	hashCode() Returns a hash code for this Boolean object.
static int	hashCode(boolean value) Returns a hash code for a boolean value; compatible with Boolean.hashCode().
static boolean	logicalAnd(boolean a, boolean b) Returns the result of applying the logical AND operator to the specified boolean operands.
static boolean	logicalOr(boolean a, boolean b) Returns the result of applying the logical OR operator to the specified boolean operands.
static boolean	logicalXor(boolean a, boolean b) Returns the result of applying the logical XOR operator to the specified boolean operands.
static boolean	parseBoolean(String s) Parses the string argument as a boolean.
String	toString() Returns a String object representing this Boolean's value.
static String	toString(boolean b) Returns a String object representing the specified boolean.
static Boolean	valueOf(String s) Returns a Boolean with a value represented by the specified string.
static Boolean	valueOf(boolean b) Returns a Boolean instance representing the specified boolean value.

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

From interface java.lang.Comparable

abstract int

compareTo(Boolean o) Compares this object with the specified object for order.

Fields

public static final Boolean FALSE

The Boolean object corresponding to the primitive value false.

public static final Boolean TRUE

The Boolean object corresponding to the primitive value true.

public static final Class<Boolean> TYPE

The Class object representing the primitive type boolean.

Public Constructors

public Boolean (boolean value)

Allocates a Boolean object representing the value argument.

Note: It is rarely appropriate to use this constructor. Unless a new instance is required, the static factory valueOf(boolean) is generally a better choice. It is likely to yield significantly better space and time performance.

Parameters

value	the value of the Boolean.

public 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". Otherwise, allocate a Boolean object representing the value false. Examples:

new Boolean("True") produces a Boolean object that represents true.
new Boolean("yes") produces a Boolean object that represents false.

Parameters

s	the string to be converted to a Boolean.

Public Methods

public boolean booleanValue ()

Returns the value of this Boolean object as a boolean primitive.

Returns

• the primitive boolean value of this object.

public static int 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))
 

Parameters

x	the first boolean to compare
y	the second boolean to compare

Returns

• the value 0 if x == y; a value less than 0 if !x && y; and a value greater than 0 if x && !y

public int compareTo (Boolean b)

Compares this Boolean instance with another.

Parameters

b	the Boolean instance to be compared

Returns

• zero if this object represents the same boolean value as the argument; a positive value if this object represents true and the argument represents false; and a negative value if this object represents false and the argument represents true

Throws

NullPointerException	if the argument is null

See Also

• Comparable

public boolean 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.

Parameters

obj	the object to compare with.

Returns

• true if the Boolean objects represent the same value; false otherwise.

public static boolean getBoolean (String name)

Returns true if and only if the system property named by the argument exists and is equal to the string "true". (Beginning with version 1.0.2 of the Java^TM platform, the test of this string is case insensitive.) A system property is accessible through getProperty, a method defined by the System class.

If there is no property with the specified name, or if the specified name is empty or null, then false is returned.

Parameters

name	the system property name.

Returns

• the boolean value of the system property.

Throws

SecurityException	for the same reasons as System.getProperty

See Also

• System.getProperty(java.lang.String)
• System.getProperty(java.lang.String, java.lang.String)

public int hashCode ()

Returns a hash code for this Boolean object.

Returns

• the integer 1231 if this object represents true; returns the integer 1237 if this object represents false.

public static int hashCode (boolean value)

Returns a hash code for a boolean value; compatible with Boolean.hashCode().

Parameters

value	the value to hash

Returns

• a hash code value for a boolean value.

public static boolean logicalAnd (boolean a, boolean b)

Returns the result of applying the logical AND operator to the specified boolean operands.

Parameters

a	the first operand
b	the second operand

Returns

• the logical AND of a and b

See Also

• BinaryOperator

public static boolean logicalOr (boolean a, boolean b)

Returns the result of applying the logical OR operator to the specified boolean operands.

Parameters

a	the first operand
b	the second operand

Returns

• the logical OR of a and b

See Also

• BinaryOperator

public static boolean logicalXor (boolean a, boolean b)

Returns the result of applying the logical XOR operator to the specified boolean operands.

Parameters

a	the first operand
b	the second operand

Returns

• the logical XOR of a and b

See Also

• BinaryOperator

public static boolean 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: Boolean.parseBoolean("True") returns true.
Example: Boolean.parseBoolean("yes") returns false.

Parameters

s	the String containing the boolean representation to be parsed

Returns

• the boolean represented by the string argument

public String toString ()

Returns a String object representing this Boolean's value. If this object represents the value true, a string equal to "true" is returned. Otherwise, a string equal to "false" is returned.

Returns

• a string representation of this object.

public static String toString (boolean b)

Returns a String object representing the specified boolean. If the specified boolean is true, then the string "true" will be returned, otherwise the string "false" will be returned.

Parameters

b	the boolean to be converted

Returns

• the string representation of the specified boolean

public static Boolean 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".

Parameters

s	a string.

Returns

• the Boolean value represented by the string.

public static Boolean 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. If a new Boolean instance is not required, this method should generally be used in preference to the constructor Boolean(boolean), as this method is likely to yield significantly better space and time performance.

Parameters

b	a boolean value.

Returns

• a Boolean instance representing b.