Bug 193467 URL hyperlink can't work in chart viewer
chart/org.eclipse.birt.chart.viewer/src/org/eclipse/birt/chart/viewer/internal/util/ChartImageManager.java
OutputStream fos = new FileOutputStream( imageFile );
		InputStream fis = generateStream( );
		byte[] buffer = new byte[1024];
		int readSize = 0;
		while ( ( readSize = fis.read( buffer ) ) != -1 )
		{
			fos.write( buffer );
		}
		fis.close( );
		fos.close( );
	}
	public File getImage( )
	{
		return imageFile;
	}
	public String getImageMap( )
	{
		return imageMap;
	}
	public synchronized static void init( ServletContext context )
	{
		if ( isInitContext )
		{
			return;
		}
		
		imageFolder = processRealPath( context, IMAGE_FOLDER, true );
		
		System.setProperty( "STANDALONE", "true" ); 
	}