Mega Code Archive
Provides common access to specifics about the version of Java that a virtual machine supports
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/*
* JBoss, Home of Professional Open Source.
* Copyright 2006, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
/**
* Provides common access to specifics about the version of <em>Java</em>
* that a virtual machine supports.
*
* Determines the version of the <em>Java Virtual Machine</em> by checking
* for the availablity of version specific classes.
*
* Classes are loaded in the following order:
* <ol>
* <li><tt>java.lang.Void</tt> was introduced in JDK 1.1</li>
* <li><tt>java.lang.ThreadLocal</tt> was introduced in JDK 1.2</li>
* <li><tt>java.lang.StrictMath</tt> was introduced in JDK 1.3</li>
* <li><tt>java.lang.StackTraceElement</tt> was introduced in JDK 1.4</li>
* <li><tt>java.lang.Enum</tt> was introduced in JDK 1.5</li>
* <li><tt>java.lang.management.LockInfo</tt> was introduced in JDK 1.6</li>
* </ol>
* </p>
*
* @version <tt>$Revision: 2240 $</tt>
* @author <a href="mailto:jason@planet57.com">Jason Dillon</a>
* @author <a href="mailto:dimitris@jboss.org">Dimitris Andreadis</a>
*/
public final class Java
{
/** Prevent instantiation */
private Java() {}
/** Java version 1.0 token */
public static final int VERSION_1_0 = 0x01;
/** Java version 1.1 token */
public static final int VERSION_1_1 = 0x02;
/** Java version 1.2 token */
public static final int VERSION_1_2 = 0x03;
/** Java version 1.3 token */
public static final int VERSION_1_3 = 0x04;
/** Java version 1.4 token */
public static final int VERSION_1_4 = 0x05;
/** Java version 1.5 token */
public static final int VERSION_1_5 = 0x06;
/** Java version 1.6 token */
public static final int VERSION_1_6 = 0x07;
/**
* Private to avoid over optimization by the compiler.
*
* @see #getVersion() Use this method to access this final value.
*/
private static final int VERSION;
/** Initialize VERSION. */
static
{
// default to 1.0
int version = VERSION_1_0;
try
{
// check for 1.1
Class.forName("java.lang.Void");
version = VERSION_1_1;
// check for 1.2
Class.forName("java.lang.ThreadLocal");
version = VERSION_1_2;
// check for 1.3
Class.forName("java.lang.StrictMath");
version = VERSION_1_3;
// check for 1.4
Class.forName("java.lang.StackTraceElement");
version = VERSION_1_4;
// check for 1.5
Class.forName("java.lang.Enum");
version = VERSION_1_5;
// check for 1.6
Class.forName("java.lang.management.LockInfo");
version = VERSION_1_6;
}
catch (ClassNotFoundException ignore)
{
}
VERSION = version;
}
/**
* Return the version of <em>Java</em> supported by the VM.
*
* @return The version of <em>Java</em> supported by the VM.
*/
public static int getVersion()
{
return VERSION;
}
/**
* Returns true if the given version identifer is equal to the
* version identifier of the current virtuial machine.
*
* @param version The version identifier to check for.
* @return True if the current virtual machine is the same version.
*/
public static boolean isVersion(final int version)
{
return VERSION == version;
}
/**
* Returns true if the current virtual machine is compatible with
* the given version identifer.
*
* @param version The version identifier to check compatibility of.
* @return True if the current virtual machine is compatible.
*/
public static boolean isCompatible(final int version)
{
// if our vm is the same or newer then we are compatible
return VERSION >= version;
}
}
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