[SalesForce] Download and save contentVersion file JAVA

Please help me with download contentversion of PDF and save to file in java.

I have a problem with base64. RestAPI return content in base64 but when I save it to file I have a blank page when I opened it in adobe reader. When I compare content with original file I see a difference. Please, what do I have to do differently?

String fileContent = 
    SFApi.getFileContentBySalesForceId("0689E00000022MKADCW");
    System.out.println(fileContent);
    assertNotNull(fileContent);
    Date date = new Date();
    String attachName = "pdf_" + date.getTime() + ".pdf";
    File outputFile = new File("c:/test/tmp/"+attachName);
    try {
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(outputFile));
        bos.write(fileContent.getBytes());
        bos.flush();
        bos.close();
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

I get content file by

run GET url :

/services/data/v40.0/sobjects/ContentVersion/0689E00000022MKADCW/VersionData

EDIT:

When I get content by widget on linux and save to file I can open file properly.

When I get content in JAVA using:

protected String getFileContentBySalesForceId(String fileSalesForceId) {
    Assert.notNull(fileSalesForceId, "Sales Force file id cannot be null.");
    HttpGet httpGet = new HttpGet(clientURL + "/services/data/v40.0/sobjects/ContentVersion/" + fileSalesForceId + "/VersionData");
    String accesToken = refreshToken();
    httpGet.addHeader("Authorization", "Bearer " + accesToken);
    HttpResponse response = null;
    String getResult = null;
    try {
        response = httpclient.execute(httpGet);
        getResult = EntityUtils.toString(response.getEntity());
        EntityUtils.consume(response.getEntity());
    } catch (ParseException | IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    final int statusCode = response.getStatusLine().getStatusCode();
    if (statusCode != HttpStatus.SC_OK) {
        log.error("Error authenticating to Force.com: " + statusCode);
        return null;
    }

    return getResult;
}

And save to file by the first method in post, I get a blank page in PDF.

Maybe I need different settings in header?

EDIT:

Need set charset

 bos.write(fileContent.getBytes("ISO-8859-1"));