Lock/Unlock RRC artifacts using OSLC API

I had a mechanism to programatically lock/unlock artifacts using OSLC for RRC. This worked fine in version 4.0.3 however is not running in the upgraded version 5.0.1 and throwing an exception 400/Bad Request.

The code snippet for locking an artifact is as follows-

https://inmbzp4102.in.dst.ibm.com:9443/rm/locks/"+artifactURI - the locking URI

public String getLockUnlockResource(String uri) {
        HttpGet get = new HttpGet(uri);
        get.setHeader("Accept", "application/xml");
        get.setHeader("OSLC-Core-Version", "2.0");
        get.setHeader("X-Jazz-CSRF-Prevent","0000UfsWrlfdGf4tF6SMIpVjnly:-1");
        String responseXML =  getResourceForLock(get);   

        return responseXML;
    }

public String getResourceForLock(HttpGet get) {
        String resourceXML="";
        System.out.println("\n=== " + get.getRequestLine());
        HttpResponse jfsResponse;

        try {
            jfsResponse = HttpUtils.sendGetForSecureDocument(
                    server, get, login, password, httpclient, JTS_Server);
            getResponseCode = jfsResponse.getStatusLine().getStatusCode();
           
            if(getResponseCode==404)
            {
                jfsResponse.getEntity().consumeContent();
                return "404";
            }
            if(jfsResponse.getStatusLine().getStatusCode() != HttpStatus.SC_OK) {
                throw new Error("Bad status: " +  jfsResponse.getStatusLine() + " for " + get.getRequestLine());
            }

            HttpEntity responseEntity = jfsResponse.getEntity();
            resourceXML = printEntity(responseEntity);
            jfsResponse.getEntity().consumeContent();
        } catch (Throwable t) {
            // TODO Auto-generated catch block
            t.printStackTrace();
        }

        return resourceXML;
    }