Encoding error in reading non-latin characters from pdf file - pdf

Question

I am trying to read Greek from a pdf file using PDFbox 1.8.7. The issue is that whatever encoding I use (Windows-1253, ISO-8859-7,UTF-8) I cannot read the greek characters. Could you provide me with an insight on what I need to set differently in the options of PDFbox in order to read the greek characters. (sample pdf file here https://www.wetransfer.com/downloads/861b3c85bb2b1eca9f10af210a8eff4820141111223938/83ff55)
My source code is the following:
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.pdfbox.cos.COSDocument;
import org.apache.pdfbox.pdfparser.PDFParser;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.font.PDFont;
import org.apache.pdfbox.pdmodel.font.PDTrueTypeFont;
import org.apache.pdfbox.util.PDFText2HTML;
import org.apache.pdfbox.util.PDFTextStripper;
/**
*
* #author Administrator
*/
public class Pdf {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
try {
PDFTextStripper pdfStripper = null;
PDDocument pdDoc = null;
COSDocument cosDoc = null;
File file = new File("C:\\themis\\Pdfs\\first.pdf");
PDFParser parser = new PDFParser(new FileInputStream(file));
parser.parse();
cosDoc = parser.getDocument();
pdDoc = new PDDocument(cosDoc);
String encoding="ISO-8859-7";
pdfStripper = new PDFTextStripper(encoding);
pdfStripper.setStartPage(1);
pdfStripper.setEndPage(2);
String parsedText = pdfStripper.getText(pdDoc);
System.out.println(parsedText);
} catch (FileNotFoundException ex) {
Logger.getLogger(PdfBMW.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(PdfBMW.class.getName()).log(Level.SEVERE, null, ex);
}
}
}