Class: java.lang.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.

Authors:
@author Arthur van Hoff
Since:
@since JDK1.0

Inheritance

Superclass tree: Implements:

Methods

  • Booleantop

    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:
    @param s the string to be converted to a Boolean .
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  • Booleantop

    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 Boolean.valueOf(boolean) is generally a better choice. It is likely to yield significantly better space and time performance.

    Parameters:
    @param value the value of the Boolean .
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  • booleanValuetop

    public boolean booleanValue()
    Returns the value of this Boolean object as a boolean primitive.
    Return:
    @return the primitive boolean value of this object.
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  • compareTotop

    public int compareTo(Boolean b)
    Compares this Boolean instance with another.
    Parameters:
    @param b the Boolean instance to be compared
    Return:
    @return 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
    Exceptions:
    @throws NullPointerException if the argument is null
    See:
    @see Comparable
    Since:
    @since 1.5
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  • equalstop

    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:
    @param obj the object to compare with.
    Return:
    @return true if the Boolean objects represent the same value; false otherwise.
    Override hierarchy:
    equals from Object
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  • getBooleantop

    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 JavaTM 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:
    @param name the system property name.
    Return:
    @return the boolean value of the system property.
    See:
    @see System.getProperty(java.lang.String)
    @see System.getProperty(java.lang.String, java.lang.String)
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  • hashCodetop

    public int hashCode()
    Returns a hash code for this Boolean object.
    Return:
    @return the integer 1231 if this object represents true ; returns the integer 1237 if this object represents false .
    Override hierarchy:
    hashCode from Object
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  • parseBooleantop

    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:
    @param s the String containing the boolean representation to be parsed
    Return:
    @return the boolean represented by the string argument
    Since:
    @since 1.5
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  • toStringtop

    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.
    Return:
    @return a string representation of this object.
    Override hierarchy:
    toString from Object
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  • toStringtop

    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:
    @param b the boolean to be converted
    Return:
    @return the string representation of the specified boolean
    Since:
    @since 1.4
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  • valueOftop

    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:
    @param s a string.
    Return:
    @return the Boolean value represented by the string.
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  • valueOftop

    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(boolean), as this method is likely to yield significantly better space and time performance.
    Parameters:
    @param b a boolean value.
    Return:
    @return a Boolean instance representing b .
    Since:
    @since 1.4
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Fields

  • FALSE

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

  • TRUE

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

  • TYPE

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