Codabar is a linear barcode symbology developed in 1972 by Pitney Bowes Corp. It was designed to be accurately read even when printed on dot-matrix printers for multi-part forms such as FedEx airbills and blood bank forms, where variants are still in use as of 2007.
This symbology is used by U.S. blood banks, photo labs, and on FedEx airbills. Because Codabar is self-checking, it does not define a check digit. This symbology starts and finishes with one of four possible characters A, B, C, or D.

Java Codabar Generator supports 16 letters.

• 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
• - (Dash), $ (Dollar), : (Colon), / (Slash), . (Point), + (Plus)

1            Linear linear = new Linear(); 
2            linear.setData("123456789"); 
3            linear.setType(Linear.CODABAR); 
4            linear.renderBarcode("c:/barcode.gif"); 

<import value="com.barcodelib.barcode.BarcodeJasperFactory"/> 

<image scaleImage="Clip" hAlign="Center"> 
    <reportElement x="50" y="110" width="515" height="120"/> 
    <graphicElement/> 
    <imageExpression class="net.sf.jasperreports.engine.JRRenderable">
     <![CDATA[new com.barcodelib.barcode.BarcodeJasperRenderer(BarcodeJasperFactory.createLinear(0, "47082163"))]]></imageExpression> 
</image>

Just call Linear object method renderBarcode, e.g. linear.renderBarcode("c:/barcode.gif");

• Set the type property to Linear.CODABAR
  Servlet Parameter: "Type".
• Set the data property with the value to encode. Type is string.
  Please keep mind that Codabar has start and stop chars.
  Valid start and stop char are 'A', 'B', 'C' and 'D'. You can choose anyone of them as your star and stop char.
  so data = start_char + barcode value + stop_char, for example, your barcode value is "12345", your data value should be 'A12345B'.
  Servlet Parameter: "Data".
• Setting up barcode image size:
  • Set property uom (Unit of Measure) for properties barWidth, barHeight, leftMargin, rightMargin, topMargin and bottomMargin.
    Default is Linear.UOM_PIXEL (0). Valid values are Linear.UOM_PIXEL (0), Linear.UOM_CM (1), Linear.UOM_Inch (2).
    Servlet Parameter: "UOM".
  • Set the X (for barcode module width) and Y (for barcode module height) properties. Both types are float.
    Servlet Parameter: "X", "Y".
  • Set the leftMargin, rightMargin, topMargin and bottomMargin properties, and types are all float.
    Servlet Parameter: "LeftMargin", "RightMargin", "TopMargin", "BottomMargin".
  • Set the barcodeWidth (barcode image width) and barcodeHeight (barcode image height) properties. Both types are float.
    Servlet Parameter: "BarcodeWidth", "BarcodeHeight".
  • Set the resolution property (Value is expressed in DPI - Dots per inch).
    Servlet Parameter: "Resolution".
• Setting up text style in barcode image:
  • Set the showText properties. If this value is true, barcode data will be displayed with the barcode.
    Servlet Parameter: "ShowText".
  • Set the textFont property. The font used to display text in barcode image.
    Servlet Parameter: "TextFont".
• Set bearerBars property, if you want to draw borders around barcode image. Value can be Linear.BEARERBAR_UNSPECIFIED (-1. let library decide whether draw bear bars or not), Linear.BEARERBAR_NONE (0. no bear bars), Linear.BEARERBAR_FRAME (1. top, bottom, left, right borders drawn), Linear.BEARERBAR_TOPBOTTOM (2. only top, bottom's are drawn).
  Servlet Parameter: "BearerBars".
• Set rotate property, if you want to rotate barcode image.
  Value can be
  0 (Linear.ANGLE_0),
  1 (Linear.ANGLE_90),
  2 (Linear.ANGLE_180),
  3 (Linear.ANGLE_270)
  Servlet Parameter: "Rotate".
• addCheckSum property is not applied here. Codabar does not require any check sum.
  Servlet Parameter: "AddCheckSum".

To set barcode image width and height, there are two ways to do it.

1) You can set barcode image width and height through properties barcodeWidth and barcodeHeight values, barcode library will render the barcode image for you.

or

2) You can set X (barcode module width) and Y (barcode module height) values, barcode library will calculate the barcodeWidth and barcodeHeight values for you, and render the barcode image.