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## java.lang
Class Boolean

    java.lang.Object
      |
      +--java.lang.Boolean

All Implemented Interfaces:
  Serializable

public final class Boolean
extends Object
implements Serializable

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`.

Since:
  JDK1.0
See Also:
  Serialized Form

Field Summary
`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` | `TYPE` The Class object representing the primitive type boolean.

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"`.

Method Summary
`boolean` | `booleanValue()` Returns the value of this `Boolean` object as a boolean primitive.
`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.
`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 inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

Field Detail

### 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 TYPE

  The Class object representing the primitive type boolean.

  Since:
    JDK1.1

Constructor Detail

### Boolean

    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`.

### 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`.

Method Detail

### 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 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 the value `true` if the string argument is not `null` and is equal, ignoring case, to the string `"true"`.

  Example: `Boolean.valueOf("True")` returns `true`.
  Example: `Boolean.valueOf("yes")` returns `false`.

  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)`, `Hashtable`

### 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()`, `Hashtable`

### 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 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:
    `name` - the system property name.
  Returns:
    the `boolean` value of the system property.
  See Also:
    `System.getProperty(java.lang.String)`, `System.getProperty(java.lang.String, java.lang.String)`

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.