Module java.base
Package java.lang

Class Boolean

java.lang.Object
java.lang.Boolean
All Implemented Interfaces:
Serializable, Comparable<Boolean>, Constable
public final class Boolean extends Object implements Serializable, Comparable<Boolean>, Constable
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.

This is a value-based class; programmers should treat instances that are equal as interchangeable and should not use instances for synchronization, or unpredictable behavior may occur. For example, in a future release, synchronization may fail.

Since:
1.0
See Also:
Serialized Form

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static Boolean
    FALSE
    The Boolean object corresponding to the primitive value false.
    static Boolean
    TRUE
    The Boolean object corresponding to the primitive value true.
    static Class<Boolean>
    TYPE
    The Class object representing the primitive type boolean.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Boolean​(boolean value)
    Deprecated, for removal: This API element is subject to removal in a future version.
    It is rarely appropriate to use this constructor.
    Boolean​(String s)
    Deprecated, for removal: This API element is subject to removal in a future version.
    It is rarely appropriate to use this constructor.

  • Method Summary

    Modifier and Type
    Method
    Description
    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.
    Optional<DynamicConstantDesc<Boolean>>
    describeConstable()
    Returns an Optional containing the nominal descriptor for this instance.
    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, ignoring case, 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​(boolean b)
    Returns a Boolean instance representing the specified boolean value.
    static Boolean
    valueOf​(String s)
    Returns a Boolean with a value represented by the specified string.

    Methods declared in class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • TRUE

      public static final Boolean TRUE
      The Boolean object corresponding to the primitive value true.

    • FALSE

      public static final Boolean FALSE
      The Boolean object corresponding to the primitive value false.

    • TYPE

      public static final Class<Boolean> TYPE
      The Class object representing the primitive type boolean.
      Since:
      1.1

  • Constructor Details

    • Boolean

      @Deprecated(since="9", forRemoval=true) public Boolean​(boolean value)
      Deprecated, for removal: This API element is subject to removal in a future version.
      It is rarely appropriate to use this constructor. The static factory valueOf(boolean) is generally a better choice, as it is likely to yield significantly better space and time performance. Also consider using the final fields TRUE and FALSE if possible.
      Allocates a Boolean object representing the value argument.
      Parameters:
      value - the value of the Boolean.

    • Boolean

      @Deprecated(since="9", forRemoval=true) public Boolean​(String s)
      Deprecated, for removal: This API element is subject to removal in a future version.
      It is rarely appropriate to use this constructor. Use parseBoolean(String) to convert a string to a boolean primitive, or use valueOf(String) to convert a string to a Boolean object.
      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, allocates a Boolean object representing the value false.
      Parameters:
      s - the string to be converted to a Boolean.

  • Method Details

    • parseBoolean

      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". Otherwise, a false value is returned, including for a null argument.

      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
      Since:
      1.5

    • booleanValue

      public boolean booleanValue()
      Returns the value of this Boolean object as a boolean primitive.
      Returns:
      the primitive boolean value of this object.

    • valueOf

      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.
      Since:
      1.4

    • valueOf

      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". Otherwise, a false value is returned, including for a null argument.
      Parameters:
      s - a string.
      Returns:
      the Boolean value represented by the string.

    • toString

      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
      Since:
      1.4

    • toString

      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.
      Overrides:
      toString in class Object
      Returns:
      a string representation of this object.

    • hashCode

      public int hashCode()
      Returns a hash code for this Boolean object.
      Overrides:
      hashCode in class Object
      Returns:
      the integer 1231 if this object represents true; returns the integer 1237 if this object represents false.
      See Also:
      Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

    • hashCode

      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.
      Since:
      1.8

    • equals

      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.
      Overrides:
      equals in class Object
      Parameters:
      obj - the object to compare with.
      Returns:
      true if the Boolean objects represent the same value; false otherwise.
      See Also:
      Object.hashCode(), HashMap

    • getBoolean

      public static boolean getBoolean​(String name)
      Returns true if and only if the system property named by the argument exists and is equal to, ignoring case, the string "true". 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)

    • compareTo

      public int compareTo​(Boolean b)
      Compares this Boolean instance with another.
      Specified by:
      compareTo in interface Comparable<Boolean>
      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
      Since:
      1.5
      See Also:
      Comparable

    • compare

      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
      Since:
      1.7

    • logicalAnd

      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
      Since:
      1.8
      See Also:
      BinaryOperator

    • logicalOr

      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
      Since:
      1.8
      See Also:
      BinaryOperator

    • logicalXor

      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
      Since:
      1.8
      See Also:
      BinaryOperator

    • describeConstable

      public Optional<DynamicConstantDesc<Boolean>> describeConstable()
      Returns an Optional containing the nominal descriptor for this instance.
      Specified by:
      describeConstable in interface Constable
      Returns:
      an Optional describing the Boolean instance
      Since:
      15