system.html

API資料大全

public static void <B>arraycopy</B>(<A HREF="../../java/lang/Object.html">Object</A>&nbsp;src,
                             int&nbsp;src_position,
                             <A HREF="../../java/lang/Object.html">Object</A>&nbsp;dst,
                             int&nbsp;dst_position,
                             int&nbsp;length)</PRE>
<DL>
<DD>Copies an array from the specified source array, beginning at the
 specified position, to the specified position of the destination array.
 A subsequence of array components are copied from the source 
 array referenced by <code>src</code> to the destination array 
 referenced by <code>dst</code>. The number of components copied is 
 equal to the <code>length</code> argument. The components at 
 positions <code>srcOffset</code> through 
 <code>srcOffset+length-1</code> in the source array are copied into 
 positions <code>dstOffset</code> through 
 <code>dstOffset+length-1</code>, respectively, of the destination 
 array. 
 <p>
 If the <code>src</code> and <code>dst</code> arguments refer to the 
 same array object, then the copying is performed as if the 
 components at positions <code>srcOffset</code> through 
 <code>srcOffset+length-1</code> were first copied to a temporary 
 array with <code>length</code> components and then the contents of 
 the temporary array were copied into positions 
 <code>dstOffset</code> through <code>dstOffset+length-1</code> of the 
 destination array. 
 <p>
 If <code>dst</code> is <code>null</code>, then a 
 <code>NullPointerException</code> is thrown.
 <p>
 If <code>src</code> is <code>null</code>, then a 
 <code>NullPointerException</code> is thrown and the destination
 array is not modified.
 <p>
 Otherwise, if any of the following is true, an 
 <code>ArrayStoreException</code> is thrown and the destination is 
 not modified: 
 <ul>
 <li>The <code>src</code> argument refers to an object that is not an 
     array. 
 <li>The <code>dst</code> argument refers to an object that is not an 
     array. 
 <li>The <code>src</code> argument and <code>dst</code> argument refer to 
     arrays whose component types are different primitive types. 
 <li>The <code>src</code> argument refers to an array with a primitive 
     component type and the <code>dst</code> argument refers to an array 
     with a reference component type. 
 <li>The <code>src</code> argument refers to an array with a reference 
     component type and the <code>dst</code> argument refers to an array 
     with a primitive component type. 
 </ul>
 <p>
 Otherwise, if any of the following is true, an 
 <code>IndexOutOfBoundsException</code> is 
 thrown and the destination is not modified: 
 <ul>
 <li>The <code>srcOffset</code> argument is negative. 
 <li>The <code>dstOffset</code> argument is negative. 
 <li>The <code>length</code> argument is negative. 
 <li><code>srcOffset+length</code> is greater than 
     <code>src.length</code>, the length of the source array. 
 <li><code>dstOffset+length</code> is greater than 
     <code>dst.length</code>, the length of the destination array. 
 </ul>
 <p>
 Otherwise, if any actual component of the source array from 
 position <code>srcOffset</code> through 
 <code>srcOffset+length-1</code> cannot be converted to the component 
 type of the destination array by assignment conversion, an 
 <code>ArrayStoreException</code> is thrown. In this case, let 
 <b><i>k</i></b> be the smallest nonnegative integer less than 
 length such that <code>src[srcOffset+</code><i>k</i><code>]</code> 
 cannot be converted to the component type of the destination 
 array; when the exception is thrown, source array components from 
 positions <code>srcOffset</code> through
 <code>srcOffset+</code><i>k</i><code>-1</code> 
 will already have been copied to destination array positions 
 <code>dstOffset</code> through
 <code>dstOffset+</code><i>k</I><code>-1</code> and no other 
 positions of the destination array will have been modified. 
 (Because of the restrictions already itemized, this
 paragraph effectively applies only to the situation where both 
 arrays have component types that are reference types.)<DD><DL>
<DT><B>Parameters:</B><DD><CODE>src</CODE> - the source array.<DD><CODE>src_position</CODE> - start position in the source array.<DD><CODE>dst</CODE> - the destination array.<DD><CODE>dst_position</CODE> - pos   start position in the destination data.<DD><CODE>length</CODE> - the number of array elements to be copied.<DT><B>Throws:</B><DD><CODE><A HREF="../../java/lang/IndexOutOfBoundsException.html">IndexOutOfBoundsException</A></CODE> - if copying would cause
               access of data outside array bounds.<DD><CODE><A HREF="../../java/lang/ArrayStoreException.html">ArrayStoreException</A></CODE> - if an element in the <code>src</code>
               array could not be stored into the <code>dest</code> array
               because of a type mismatch.<DD><CODE><A HREF="../../java/lang/NullPointerException.html">NullPointerException</A></CODE> - if either <code>src</code> or 
               <code>dst</code> is <code>null</code>.</DL>
</DD>
</DL>
<HR>

<A NAME="identityHashCode(java.lang.Object)"><!-- --></A><H3>
identityHashCode</H3>
<PRE>
public static int <B>identityHashCode</B>(<A HREF="../../java/lang/Object.html">Object</A>&nbsp;x)</PRE>
<DL>
<DD>Returns the same hashcode for the given object as
 would be returned by the default method hashCode(),
 whether or not the given object's class overrides
 hashCode().
 The hashcode for the null reference is zero.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>x</CODE> - object for which the hashCode is to be calculated<DT><B>Returns:</B><DD>the hashCode<DT><B>Since: </B><DD>JDK1.1</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="getProperties()"><!-- --></A><H3>
getProperties</H3>
<PRE>
public static <A HREF="../../java/util/Properties.html">Properties</A> <B>getProperties</B>()</PRE>
<DL>
<DD>Determines the current system properties. 
 <p>
 First, if there is a security manager, its 
 <code>checkPropertiesAccess</code> method is called with no 
 arguments. This may result in a security exception. 
 <p>
 The current set of system properties for use by the 
 <A HREF="../../java/lang/System.html#getProperty(java.lang.String)"><CODE>getProperty(String)</CODE></A> method is returned as a 
 <code>Properties</code> object. If there is no current set of 
 system properties, a set of system properties is first created and 
 initialized. This set of system properties always includes values 
 for the following keys: 
 <table>
 <tr><th>Key</th>
     <th>Description of Associated Value</th></tr>
 <tr><td><code>java.version</code></td>
     <td>Java Runtime Environment version</td></tr>
 <tr><td><code>java.vendor</code></td>
     <td>Java Runtime Environment vendor</td></tr
 <tr><td><code>java.vendor.url</code></td>
     <td>Java vendor URL</td></tr>
 <tr><td><code>java.home</code></td>
     <td>Java installation directory</td></tr>
 <tr><td><code>java.vm.specification.version</code></td>
     <td>Java Virtual Machine specification version</td></tr>
 <tr><td><code>java.vm.specification.vendor</code></td>
     <td>Java Virtual Machine specification vendor</td></tr>
 <tr><td><code>java.vm.specification.name</code></td>
     <td>Java Virtual Machine specification name</td></tr>
 <tr><td><code>java.vm.version</code></td>
     <td>Java Virtual Machine implementation version</td></tr>
 <tr><td><code>java.vm.vendor</code></td>
     <td>Java Virtual Machine implementation vendor</td></tr>
 <tr><td><code>java.vm.name</code></td>
     <td>Java Virtual Machine implementation name</td></tr>
 <tr><td><code>java.specification.version</code></td>
     <td>Java Runtime Environment specification  version</td></tr>
 <tr><td><code>java.specification.vendor</code></td>
     <td>Java Runtime Environment specification  vendor</td></tr>
 <tr><td><code>java.specification.name</code></td>
     <td>Java Runtime Environment specification  name</td></tr>
 <tr><td><code>java.class.version</code></td>
     <td>Java class format version number</td></tr>
 <tr><td><code>java.class.path</code></td>
     <td>Java class path</td></tr>
 <tr><td><code>java.ext.dirs</code></td>
     <td>Path of extension directory or directories</td></tr>
 <tr><td><code>os.name</code></td>
     <td>Operating system name</td></tr>
 <tr><td><code>os.arch</code></td>
     <td>Operating system architecture</td></tr>
 <tr><td><code>os.version</code></td>
     <td>Operating system version</td></tr>
 <tr><td><code>file.separator</code></td>
     <td>File separator ("/" on UNIX)</td></tr>
 <tr><td><code>path.separator</code></td>
     <td>Path separator (":" on UNIX)</td></tr>
 <tr><td><code>line.separator</code></td>
     <td>Line separator ("\n" on UNIX)</td></tr>
 <tr><td><code>user.name</code></td>
     <td>User's account name</td></tr>
 <tr><td><code>user.home</code></td>
     <td>User's home directory</td></tr>
 <tr><td><code>user.dir</code></td>
     <td>User's current working directory</td></tr>
 </table>
 <p>
 Note that even if the security manager does not permit the 
 <code>getProperties</code> operation, it may choose to permit the 
 <A HREF="../../java/lang/System.html#getProperty(java.lang.String)"><CODE>getProperty(String)</CODE></A> operation.<DD><DL>
<DT><B>Returns:</B><DD>the system properties<DT><B>Throws:</B><DD><CODE><A HREF="../../java/lang/SecurityException.html">SecurityException</A></CODE> - if a security manager exists and its  
             <code>checkPropertiesAccess</code> method doesn't allow access 
              to the system properties.<DT><B>See Also: </B><DD><A HREF="../../java/lang/System.html#setProperties(java.util.Properties)"><CODE>setProperties(java.util.Properties)</CODE></A>, 
<A HREF="../../java/lang/SecurityException.html"><CODE>SecurityException</CODE></A>, 
<A HREF="../../java/lang/SecurityManager.html#checkPropertiesAccess()"><CODE>SecurityManager.checkPropertiesAccess()</CODE></A>, 
<A HREF="../../java/util/Properties.html"><CODE>Properties</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="setProperties(java.util.Properties)"><!-- --></A><H3>
setProperties</H3>
<PRE>
public static void <B>setProperties</B>(<A HREF="../../java/util/Properties.html">Properties</A>&nbsp;props)</PRE>
<DL>
<DD>Sets the system properties to the <code>Properties</code> 
 argument. 
 <p>
 First, if there is a security manager, its 
 <code>checkPropertiesAccess</code> method is called with no 
 arguments. This may result in a security exception. 
 <p>
 The argument becomes the current set of system properties for use 
 by the <A HREF="../../java/lang/System.html#getProperty(java.lang.String)"><CODE>getProperty(String)</CODE></A> method. If the argument is 
 <code>null</code>, then the current set of system properties is 
 forgotten.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>props</CODE> - the new system properties.<DT><B>Throws:</B><DD><CODE><A HREF="../../java/lang/SecurityException.html">SecurityException</A></CODE> - if a security manager exists and its  
             <code>checkPropertiesAccess</code> method doesn't allow access 
              to the system properties.<DT><B>See Also: </B><DD><A HREF="../../java/lang/System.html#getProperties()"><CODE>getProperties()</CODE></A>, 
<A HREF="../../java/util/Properties.html"><CODE>Properties</CODE></A>, 
<A HREF="../../java/lang/SecurityException.html"><CODE>SecurityException</CODE></A>, 
<A HREF="../../java/lang/SecurityManager.html#checkPropertiesAccess()"><CODE>SecurityManager.checkPropertiesAccess()</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="getProperty(java.lang.String)"><!-- --></A><H3>
getProperty</H3>
<PRE>
public static <A HREF="../../java/lang/String.html">String</A> <B>getProperty</B>(<A HREF="../../java/lang/String.html">String</A>&nbsp;key)</PRE>
<DL>
<DD>Gets the system property indicated by the specified key. 
 <p>
 First, if there is a security manager, its 
 <code>checkPropertyAccess</code> method is called with the key as 
 its argument. This may result in a SecurityException. 
 <p>
 If there is no current set of system properties, a set of system 
 properties is first created and initialized in the same manner as 
 for the <code>getProperties</code> method.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>key</CODE> - the name of the system property.<DT><B>Returns:</B><DD>the string value of the system property,
             or <code>null</code> if there is no property with that key.<DT><B>Throws:</B><DD><CODE><A HREF="../../java/lang/SecurityException.html">SecurityException</A></CODE> - if a security manager exists and its  
             <code>checkPropertyAccess</code> method doesn't allow
              access to the specified system property.<DD><CODE><A HREF="../../java/lang/NullPointerException.html">NullPointerException</A></CODE> - if <code>key</code> is
             <code>null</code>.<DD><CODE><A HREF="../../java/lang/IllegalArgumentException.html">IllegalArgumentException</A></CODE> - if <code>key</code> is empty.<DT><B>See Also: </B><DD><A HREF="../../java/lang/System.html#setProperty(java.lang.String, java.lang.String)"><CODE>setProperty(java.lang.String, java.lang.String)</CODE></A>, 
<A HREF="../../java/lang/SecurityException.html"><CODE>SecurityException</CODE></A>, 
<A HREF="../../java/lang/SecurityManager.html#checkPropertyAccess(java.lang.String)"><CODE>SecurityManager.checkPropertyAccess(java.lang.String)</CODE></A>, 
<A HREF="../../java/lang/System.html#getProperties()"><CODE>getProperties()</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="getProperty(java.lang.String, java.lang.String)"><!-- --></A><H3>
getProperty</H3>
<PRE>
public static <A HREF="../../java/lang/String.html">String</A> <B>getProperty</B>(<A HREF="../../java/lang/String.html">String</A>&nbsp;key,
                                 <A HREF="../../java/lang/String.html">String</A>&nbsp;def)</PRE>
<DL>
<DD>Gets the system property indicated by the specified key. 
 <p>
 First, if there is a security manager, its 
 <code>checkPropertyAccess</code> method is called with the 
 <code>key</code> as its argument. 
 <p>
 If there is no current set of system properties, a set of system 
 properties is first created and initialized in the same manner as 
 for the <code>getProperties</code> method.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>key</CODE> - the name of the system property.<DD><CODE>def</CODE> - a default value.<DT><B>Returns:</B><DD>the string value of the system property,
             or the default value if there is no property with that key.<DT><B>Throws:</B><DD><CODE><A HREF="../../java/lang/SecurityException.html">SecurityException</A></CODE> - if a security manager exists and its  
             <code>checkPropertyAccess</code> method doesn't allow
             access to the specified system property.<DD><CODE><A HREF="../../java/lang/NullPointerException.html">NullPointerException</A></CODE> - if <code>key</code> is
             <code>null</code>.<DD><CODE><A HREF="../../java/lang/IllegalArgumentException.html">IllegalArgumentException</A></CODE> - if <code>key</code> is empty.<DT><B>See Also: </B><DD><A HREF="../../java/lang/System.html#setProperty(java.lang.String, java.lang.String)"><CODE>setProperty(java.lang.String, java.lang.String)</CODE></A>, 
<A HREF="../../java/lang/SecurityManager.html#checkPropertyAccess(java.lang.String)"><CODE>SecurityManager.checkPropertyAccess(java.lang.String)</CODE></A>, 
<A HREF="../../java/lang/System.html#getProperties()"><CODE>getProperties()</CODE></A></DL>
</DD>
</DL>
<HR>