1 /*

     2  * Copyright (c) 1998, 2017, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 /**

    27  * Provides classes that are fundamental to the design of the Java

    28  * programming language. The most important classes are {@code

    29  * Object}, which is the root of the class hierarchy, and {@code

    30  * Class}, instances of which represent classes at run time.

    31  *

    32  * <p>Frequently it is necessary to represent a value of primitive

    33  * type as if it were an object. The wrapper classes {@code Boolean},

    34  * {@code Character}, {@code Integer}, {@code Long}, {@code Float},

    35  * and {@code Double} serve this purpose.  An object of type {@code

    36  * Double}, for example, contains a field whose type is double,

    37  * representing that value in such a way that a reference to it can be

    38  * stored in a variable of reference type.  These classes also provide

    39  * a number of methods for converting among primitive values, as well

    40  * as supporting such standard methods as equals and hashCode.  The

    41  * {@code Void} class is a non-instantiable class that holds a

    42  * reference to a {@code Class} object representing the type void.

    43  *

    44  * <p>The class {@code Math} provides commonly used mathematical

    45  * functions such as sine, cosine, and square root. The classes {@code

    46  * String}, {@code StringBuffer}, and {@code StringBuilder} similarly

    47  * provide commonly used operations on character strings.

    48  *

    49  * <p>Classes {@code ClassLoader}, {@code Process}, {@code

    50  * ProcessBuilder}, {@code Runtime}, {@code SecurityManager}, and

    51  * {@code System} provide "system operations" that manage the dynamic

    52  * loading of classes, creation of external processes, host

    53  * environment inquiries such as the time of day, and enforcement of

    54  * security policies.

    55  *

    56  * <p>Class {@code Throwable} encompasses objects that may be thrown

    57  * by the {@code throw} statement. Subclasses of {@code Throwable}

    58  * represent errors and exceptions.

    59  *

    60  * <a id="charenc"></a>

    61  * <h3>Character Encodings</h3>

    62  *

    63  * The specification of the {@link java.nio.charset.Charset

    64  * java.nio.charset.Charset} class describes the naming conventions

    65  * for character encodings as well as the set of standard encodings

    66  * that must be supported by every implementation of the Java

    67  * platform.

    68  *

    69  * @since 1.0

    70  */

    71 package java.lang;