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| </style><!-- ======== START OF CLASS DATA ======== --> |
| <H2> |
| <FONT SIZE="-1"> |
| java.lang</FONT> |
| <BR> |
| Class String</H2> |
| <PRE> |
| <A HREF="../../java/lang/Object.html" title="class in java.lang">java.lang.Object</A> |
| <IMG SRC="../../resources/inherit.gif" ALT="extended by "><B>java.lang.String</B> |
| </PRE> |
| <DL><DL> |
| <DT><BR><PRE>public final class <B>String</B><DT><BR>extends <A HREF="../../java/lang/Object.html" title="class in java.lang">Object</A><DT><BR>implements <A HREF="../../java/io/Serializable.html" title="interface in java.io">Serializable</A>, <A HREF="../../java/lang/Comparable.html" title="interface in java.lang">Comparable</A><<A HREF="../../java/lang/String.html" title="class in java.lang">String</A>>, <A HREF="../../java/lang/CharSequence.html" title="interface in java.lang">CharSequence</A></DL> |
| </PRE> |
| |
| <DT><B>All Implemented Interfaces:</B> <DD><A HREF="../../java/io/Serializable.html" title="interface in java.io">Serializable</A>, <A HREF="../../java/lang/CharSequence.html" title="interface in java.lang">CharSequence</A>, <A HREF="../../java/lang/Comparable.html" title="interface in java.lang">Comparable</A><<A HREF="../../java/lang/String.html" title="class in java.lang">String</A>></DD> |
| </DL> |
| <P> The <code>String</code> class represents character strings. All |
| string literals in Java programs, such as <code>"abc"</code>, are |
| implemented as instances of this class. |
| <p> |
| Strings are constant; their values cannot be changed after they |
| are created. String buffers support mutable strings. |
| Because String objects are immutable they can be shared. For example: |
| <p><blockquote><pre> |
| String str = "abc"; |
| </pre></blockquote><p> |
| is equivalent to: |
| <p><blockquote><pre> |
| char data[] = {'a', 'b', 'c'}; |
| String str = new String(data); |
| </pre></blockquote><p> |
| Here are some more examples of how strings can be used: |
| <p><blockquote><pre> |
| System.out.println("abc"); |
| String cde = "cde"; |
| System.out.println("abc" + cde); |
| String c = "abc".substring(2,3); |
| String d = cde.substring(1, 2); |
| </pre></blockquote> |
| <p> |
| The class <code>String</code> includes methods for examining |
| individual characters of the sequence, for comparing strings, for |
| searching strings, for extracting substrings, and for creating a |
| copy of a string with all characters translated to uppercase or to |
| lowercase. Case mapping is based on the Unicode Standard version |
| specified by the <A HREF="../../java/lang/Character.html" title="class in java.lang"><CODE>Character</CODE></A> class. |
| <p> |
| The Java language provides special support for the string |
| concatenation operator ( + ), and for conversion of |
| other objects to strings. String concatenation is implemented |
| through the <code>StringBuilder</code>(or <code>StringBuffer</code>) |
| class and its <code>append</code> method. |
| String conversions are implemented through the method |
| <code>toString</code>, defined by <code>Object</code> and |
| inherited by all classes in Java. For additional information on |
| string concatenation and conversion, see Gosling, Joy, and Steele, |
| <i>The Java Language Specification</i>. |
| |
| <p> Unless otherwise noted, passing a <tt>null</tt> argument to a constructor |
| or method in this class will cause a <A HREF="../../java/lang/NullPointerException.html" title="class in java.lang"><CODE>NullPointerException</CODE></A> to be |
| thrown. |
| |
| <p>A <code>String</code> represents a string in the UTF-16 format |
| in which <em>supplementary characters</em> are represented by <em>surrogate |
| pairs</em> (see the section <a href="Character.html#unicode">Unicode |
| Character Representations</a> in the <code>Character</code> class for |
| more information). |
| Index values refer to <code>char</code> code units, so a supplementary |
| character uses two positions in a <code>String</code>. |
| <p>The <code>String</code> class provides methods for dealing with |
| Unicode code points (i.e., characters), in addition to those for |
| dealing with Unicode code units (i.e., <code>char</code> values). |
| <P> |
| |
| <P> |
| <DL> |
| <DT><B>Since:</B></DT> |
| <DD>JDK1.0</DD> |
| <DT><B>See Also:</B><DD><A HREF="../../java/lang/Object.html#toString()"><CODE>Object.toString()</CODE></A>, |
| <A HREF="../../java/lang/StringBuffer.html" title="class in java.lang"><CODE>StringBuffer</CODE></A>, |
| <A HREF="../../java/lang/StringBuilder.html" title="class in java.lang"><CODE>StringBuilder</CODE></A>, |
| <A HREF="../../java/nio/charset/Charset.html" title="class in java.nio.charset"><CODE>Charset</CODE></A>, |
| <A HREF="../../serialized-form.html#java.lang.String">Serialized Form</A></DL> |
| |
| <P> |
| </HTML> |