I am trying to display ukranian character in jasper report as a pdf file. but it is not diaplaying in pdf format.
when I export report to all other format like html,
Since jasper report v5, v6 the correct way to display characters in pdf is to use font-extension
For more information see these question on stackoverflow:
Jasper Reports PDF doesn't export cyrillic values
How can I display "$£Ω€απ⅔" in Jasperserver PDF using iReport?
register font in JVM
Font myFont = Font.createFont(Font.TRUETYPE_FONT, new File("pathToCyrillicFont"));
GraphicsEnvironment.getLocalGraphicsEnvironment().registerFont(myFont); 
add to Cyrillic field this:
<textElement>
   <font
                  fontName="fontName"
                  pdfFontName="pathToCyrillicFont"
                  size="13"
                  isBold="false"
                  isItalic="false"
                  isUnderline="false"
                  isPdfEmbedded ="true"
                  pdfEncoding ="Cp1251"
                  isStrikeThrough="false"
   /> 
 </textElement>
Enjoy!
First, make sure you have the right encoding:
JRPdfExporter exporter = new JRPdfExporter();
exporter.setParameter(JRExporterParameter.CHARACTER_ENCODING, "UTF-8");
Then you should change the fonts to ones that support cyrillic. This is done via styles:
public void addPdfFontsToStyles(JRStyle[] styles) {
    if (styles != null) {
        for (JRStyle style : styles) {
            if (style.getName().equals("reportStyle")) {
                style.setPdfFontName("/com/yourcompany/fonts/times.ttf");
                style.setBlankWhenNull(true);
            }
            if (style.getName().equals("reportBoldStyle")) {
                style.setPdfFontName("/com/yourcompany/fonts/timesbd.ttf");
                style.setBlankWhenNull(true);
            }
        }
    }
}
And invoke this method with addPdfFontsToStyles(jasperReport.getStyles());
Of course, the prerequisites are:
That should do it (I'm taking the code from a working cyrilic application)
Set some text field properties at iReport. Use font DejaVu Sans. Set pdf encoding to Cp1251 and isPdfEmbedded to true.
Ex.: <font fontName="DejaVu Sans" isStrikeThrough="false" pdfEncoding="Cp1251" isPdfEmbedded="true" />
jasperreports fonts as maven dependency:
<dependency>
    <groupId>net.sf.jasperreports</groupId>
    <artifactId>jasperreports-fonts</artifactId>
</dependency>