system.java

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     * <li>The <code>src</code> argument and <code>dest</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>dest</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>dest</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>srcPos</code> argument is negative.
     * <li>The <code>destPos</code> argument is negative.
     * <li>The <code>length</code> argument is negative.
     * <li><code>srcPos+length</code> is greater than
     *     <code>src.length</code>, the length of the source array.
     * <li><code>destPos+length</code> is greater than
     *     <code>dest.length</code>, the length of the destination array.
     * </ul>
     * <p>
     * Otherwise, if any actual component of the source array from
     * position <code>srcPos</code> through
     * <code>srcPos+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[srcPos+</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>srcPos</code> through
     * <code>srcPos+</code><i>k</i><code>-1</code>
     * will already have been copied to destination array positions
     * <code>destPos</code> through
     * <code>destPos+</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.)
     *
     * @param      src      the source array.
     * @param      srcPos   starting position in the source array.
     * @param      dest     the destination array.
     * @param      destPos  starting position in the destination data.
     * @param      length   the number of array elements to be copied.
     * @exception  IndexOutOfBoundsException  if copying would cause
     *               access of data outside array bounds.
     * @exception  ArrayStoreException  if an element in the <code>src</code>
     *               array could not be stored into the <code>dest</code> array
     *               because of a type mismatch.
     * @exception  NullPointerException if either <code>src</code> or
     *               <code>dest</code> is <code>null</code>.
     */
    public static native void arraycopy(Object src,  int  srcPos,
                                        Object dest, int destPos,
                                        int length);

    /**
     * Returns the same hash code for the given object as
     * would be returned by the default method hashCode(),
     * whether or not the given object's class overrides
     * hashCode().
     * The hash code for the null reference is zero.
     *
     * @param x object for which the hashCode is to be calculated
     * @return  the hashCode
     * @since   JDK1.1
     */
    public static native int identityHashCode(Object x);

    /**
     * System properties. The following properties are guaranteed to be defined:
     * <dl>
     * <dt>java.version		<dd>Java version number
     * <dt>java.vendor		<dd>Java vendor specific string
     * <dt>java.vendor.url	<dd>Java vendor URL
     * <dt>java.home		<dd>Java installation directory
     * <dt>java.class.version	<dd>Java class version number
     * <dt>java.class.path	<dd>Java classpath
     * <dt>os.name		<dd>Operating System Name
     * <dt>os.arch		<dd>Operating System Architecture
     * <dt>os.version		<dd>Operating System Version
     * <dt>file.separator	<dd>File separator ("/" on Unix)
     * <dt>path.separator	<dd>Path separator (":" on Unix)
     * <dt>line.separator	<dd>Line separator ("\n" on Unix)
     * <dt>user.name		<dd>User account name
     * <dt>user.home		<dd>User home directory
     * <dt>user.dir		<dd>User's current working directory
     * </dl>
     */

    private static Properties props;
    private static native Properties initProperties(Properties props);

    /**
     * CLDC/MIDP properties.
     *	microedition.platform
     *	microedition.endocing
     *	microedition.configuration
     *	microedition.profiles
     *  microedition.locale
     */
    private static Properties midpProps;
    private static native Properties initCldcMidpProperties(Properties midpProps);

    /**
     * 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 
     * {@link #getProperty(String)} 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 summary="Shows property keys and associated values">
     * <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.library.path</code></td>
     *     <td>List of paths to search when loading libraries</td></tr>
     * <tr><td><code>java.io.tmpdir</code></td>
     *     <td>Default temp file path</td></tr>
     * <tr><td><code>java.compiler</code></td>
     *     <td>Name of JIT compiler to use</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>
     * Multiple paths in a system property value are separated by the path
     * separator character of the platform.
     * <p>
     * Note that even if the security manager does not permit the
     * <code>getProperties</code> operation, it may choose to permit the
     * {@link #getProperty(String)} operation.
     *
     * @return     the system properties
     * @exception  SecurityException  if a security manager exists and its
     *             <code>checkPropertiesAccess</code> method doesn't allow access
     *              to the system properties.
     * @see        #setProperties
     * @see        java.lang.SecurityException
     * @see        java.lang.SecurityManager#checkPropertiesAccess()
     * @see        java.util.Properties
     */
    public static Properties getProperties() {
	if (security != null) {
	    security.checkPropertiesAccess();
	}

        /*
         * If there are dynamic properties, resolve them all and
         * add to the returned properties.
         */
        DynamicProperties.addSnapshot(props);

        return props;
    }

    /**
     * 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 {@link #getProperty(String)} method. If the argument is
     * <code>null</code>, then the current set of system properties is
     * forgotten.
     *
     * @param      props   the new system properties.
     * @exception  SecurityException  if a security manager exists and its
     *             <code>checkPropertiesAccess</code> method doesn't allow access
     *              to the system properties.
     * @see        #getProperties
     * @see        java.util.Properties
     * @see        java.lang.SecurityException
     * @see        java.lang.SecurityManager#checkPropertiesAccess()
     */
    public static void setProperties(Properties props) {
	if (security != null) {
	    security.checkPropertiesAccess();
	}
        if (props == null) {
            props = new Properties();
            initProperties(props);
        }
	System.props = props;
    }

    /**
     * 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.
     *
     * @param      key   the name of the system property.
     * @return     the string value of the system property,
     *             or <code>null</code> if there is no property with that key.
     *
     * @exception  SecurityException  if a security manager exists and its
     *             <code>checkPropertyAccess</code> method doesn't allow
     *              access to the specified system property.
     * @exception  NullPointerException if <code>key</code> is
     *             <code>null</code>.
     * @exception  IllegalArgumentException if <code>key</code> is empty.
     * @see        #setProperty
     * @see        java.lang.SecurityException
     * @see        java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
     * @see        java.lang.System#getProperties()
     */
    public static String getProperty(String key) {
	if (key == null) {
	    throw new NullPointerException("key can't be null");
	}
	if (key.equals("")) {
	    throw new IllegalArgumentException("key can't be empty");
	}
	if (security != null) {
	    security.checkPropertyAccess(key);
	}

        /* Check for the property provider first */
        PropertyProvider provider = DynamicProperties.get(key);
        if (provider != null) {
            return provider.getValue(key, false);
        }

        /*
         * MIDP Property Support
         * 
         * Allow MIDP properties to override base properties in a MIDP
         * context.
         */
        if (sun.misc.CVM.isMIDPContext()) {
            String prop = midpProps.getProperty(key);
            if (prop != null) {
                return prop;
            }
        }

        return props.getProperty(key);
    }

    /**
     * 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.
     *
     * @param      key   the name of the system property.
     * @param      def   a default value.
     * @return     the string value of the system property,
     *             or the default value if there is no property with that key.
     *
     * @exception  SecurityException  if a security manager exists and its
     *             <code>checkPropertyAccess</code> method doesn't allow
     *             access to the specified system property.
     * @exception  NullPointerException if <code>key</code> is
     *             <code>null</code>.
     * @exception  IllegalArgumentException if <code>key</code> is empty.
     * @see        #setProperty
     * @see        java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
     * @see        java.lang.System#getProperties()
     */
    public static String getProperty(String key, String def) {
	if (key == null) {
	    throw new NullPointerException("key can't be null");
	}
	if (key.equals("")) {
	    throw new IllegalArgumentException("key can't be empty");
	}
	if (security != null) {