Issue while connect QC after migrating to 11.52 from Java code

Hello,

I have developed a tool in JAVA to access Quality Center version 9 through Java code.
I have used COM4J based approach to generate the Java code out of OTAClient.dll file.
The command used to generate the API -
java -jar tlbimp.jar -o hpqc -p com.qc OtaClient.dll

I have downloaded the COM4J jar from below URL -
http://java.net/projects/com4j/downloads

OtaClient.dll taken from path - C:\Program Files (x86)\Common Files\Mercury Interactive\Quality Center\

I used below code to connect to QC -

ITDConnection qcConnect = ClassFactory.createTDConnection();
qcConnect.initConnectionEx("http://myurl/qcbin");

qcConnect.connectProjectEx("DOMAIN", "PROJECT",
"USER",
"pass");

It was all working fine till we migrated to QC 11.52 version.

After migrating when I used same code to run the application - It throws below exception on line
qcConnect.connectProjectEx();

Exception in thread "main" com4j.ComException: 800403ea (Unknown error) : Failed to Login : .\invoke.cpp:517
at com4j.Wrapper.invoke(Wrapper.java:166)
at com.sun.proxy.$Proxy5.connectProjectEx(Unknown Source)

Then I used new OTAClient.dll which I got from path - C:\Users\XXXXX\AppData\Local\HP\ALM-Client\qcalm\

I got below error in line ITDConnection qcConnect = ClassFactory.createTDConnection();

Exception in thread "main" com4j.ExecutionException: com4j.ComException: 80004002 QueryInterface failed : No such interface supported : .\com4j.cpp:163
at com4j.ComThread.execute(ComThread.java:203)
at com4j.Task.execute(Task.java:25)
at com4j.COM4J.createInstance(COM4J.java:97)
at com4j.COM4J.createInstance(COM4J.java:72)
at com.qc.ClassFactory.createTDConnection(ClassFactory.java:16)

Please help me how to resolve the issue.
- Do I need to use new COM4J library?
- If we can use REST also to fetch defect from QC, please let me know where will I get the REST API Client for the QC.

Any help is appreciated.

Thanks,
Jyoti Balabantaray