I have
$ java -version
java version "1.6.0_13"
Java(TM) SE Runtime Environment (build 1.6.0_13-b03)
Java HotSpot(TM) 64-Bit Server VM (build 11.3-b02, mixed mode)
that is the latest official version. It is not a beta.
I think this bit of code to take apart java version numbers might help
you understand how they work.
/*
* @(#)VersionCheck.java
*
* Summary: Check that Java version is sufficiently recent
*
* Copyright: (c) 1997-2009 Roedy Green, Canadian Mind Products,
http://mindprod.com
*
* Licence: This software may be copied and used freely for any
purpose but military.
* see
http://mindprod.com/contact/nonmil.html
*
* Created with: IntelliJ IDEA IDE.
*
* Version History:
* 1.0 1997-03-23 - initial.
* 1.1 1998-11-10 - add dates
* 1.2 1998-12-14 - add isJavaVersionOK
* 1.3 1999-08-24 - add leftPad, rightPad, smarter rep.
isJavaVersionOK now handles 1.3beta.
* 1.4 2002-08-17 - add quoteSQL
* 1.5 2005-07-14 - split off from Misc, allow for compilation with
old compiler.
* 1.7 2006-03-04 - reformat with IntelliJ, provide Javadoc
*/
package com.mindprod.common11;
import java.awt.Color;
import java.awt.Container;
import java.awt.TextArea;
/**
* Check that Java version is sufficiently recent
*
* @author Roedy Green, Canadian Mind Products
* @version 1.7 2006-03-04 -
*
*/
public final class VersionCheck
{
// ------------------------------ FIELDS
------------------------------
/**
* true if you want extra debugging output and test code
*/
static final boolean DEBUGGING = false;
// -------------------------- PUBLIC STATIC METHODS
--------------------------
/**
* Ensures Java runtime version e.g. 1.1.7 is sufficiently recent.
Based on code by Dr. Tony Dahlman
* <
[email protected]>
*
* @param wantedMajor java major version e.g. 1
* @param wantedMinor Java minor version e.g. 1
* @param wantedBugFix Java bugfix version e.g. 7
*
* @return true if JVM version running is equal to or more recent
than (higher than) the level specified.
*/
public static boolean isJavaVersionOK( int wantedMajor,
int wantedMinor,
int wantedBugFix )
{
try
{
try
{
// java.version will have form 1.1.7A, 11, 1.1., 1.1,
1.3beta,
// 1.4.2_05 or 1.4.1-rc
// It may be gibberish. It may be undefined.
// We have do deal with all this malformed garbage.
// Because incompetents run the world,
// it is not nicely formatted for us in three fields.
String ver = System.getProperty( "java.version" );
if ( ver == null )
{
return false;
}
ver = ver.trim();
if ( ver.length() < 2 )
{
return false;
}
int dex = ver.indexOf( '.' );
if ( dex < 0 )
{
// provide missing dot
ver = ver.charAt( 0 ) + '.' + ver.substring( 1 );
dex = 1;
}
int gotMajor = Integer.parseInt( ver.substring( 0, dex
) );
if ( DEBUGGING )
{
System.out.println( "major:" + gotMajor );
}
if ( gotMajor < wantedMajor )
{
return false;
}
if ( gotMajor > wantedMajor )
{
return true;
}
// chop off major and first dot.
ver = ver.substring( dex + 1 );
// chop trailing "beta"
if ( ver.endsWith( "beta" ) )
{
ver = ver.substring( 0, ver.length() -
"beta".length() );
}
// chop trailing "-rc"
if ( ver.endsWith( "-rc" ) )
{
ver = ver.substring( 0, ver.length() -
"-rc".length() );
}
// chop any trailing _nn
dex = ver.lastIndexOf( '_' );
if ( dex >= 0 )
{
ver = ver.substring( 0, dex );
}
// chop any trailing letter as in 1.1.7A,
// but convert 1.1.x or 1.1.X to 1.1.9
char ch = ver.charAt( ver.length() - 1 );
if ( !Character.isDigit( ch ) )
{
ver = ver.substring( 0, ver.length() - 1 );
if ( ch == 'x' || ch == 'X' )
{
ver += '9';
}
}
// check minor version
dex = ver.indexOf( '.' );
if ( dex < 0 )
{
// provide missing BugFix number as in 1.2 or 1.0
ver += ".0";
dex = ver.indexOf( '.' );
}
int gotMinor = Integer.parseInt( ver.substring( 0, dex
) );
if ( DEBUGGING )
{
System.out.println( "minor:" + gotMinor );
}
if ( gotMinor < wantedMinor )
{
return false;
}
if ( gotMinor > wantedMinor )
{
return true;
}
// was equal, need to examine third field.
// check bugfix version
ver = ver.substring( dex + 1 );
int gotBugFix = Integer.parseInt( ver );
if ( DEBUGGING )
{
System.out.println( "bugFix:" + gotBugFix );
}
return ( gotBugFix >= wantedBugFix );
}
catch ( NumberFormatException e )
{
if ( DEBUGGING )
{
System.out.println( "number format" +
e.getMessage() );
}
return false;
}// end catch
}
catch ( StringIndexOutOfBoundsException e )
{
if ( DEBUGGING )
{
System.out.println( "out of bounds:" + e.getMessage()
);
}
return false;
}// end catch
}// end isJavaVersionOK
/**
* use in a paint routine if Java version is not ok, usually
tested statically.
*
* @param wantedMajor java major version e.g. 1
* @param wantedMinor Java minor version e.g. 1
* @param wantedBugFix Java bugfix version e.g. 7
* @param container container to add an error message
component.
*
* @return true if version is ok
*/
public static boolean isJavaVersionOK( int wantedMajor,
int wantedMinor,
int wantedBugFix,
Container container )
{
if ( isJavaVersionOK( wantedMajor, wantedMinor, wantedBugFix )
)
{
return true;
}
else
{
String error =
"Error: You need Java "
+ wantedMajor
+ "."
+ wantedMinor
+ "."
+ wantedBugFix
+ " or later to run this Applet.\n"
+ "You are currently running under Java "
+ System.getProperty( "java.version" )
+ ".\n"
+ "Get the latest Java from
http://java.com/en/index.jsp";
TextArea complain =
new TextArea( error, 3, 42,
TextArea.SCROLLBARS_NONE );
complain.setEditable( false );
complain.setBackground( Color.white );
complain.setForeground( Color.red );
complain.setSize( 300, 50 );
container.setLayout( null );
container.add( complain );
System.err.println( error );
return false;
}
}
// --------------------------- CONSTRUCTORS
---------------------------
/**
* VersionCheck contains only static methods.
*/
private VersionCheck()
{
}
}
--
Roedy Green Canadian Mind Products
http://mindprod.com
Now for something completely different:
