Get Test cases from Test Plan using OTA

I have the following structure in QC

Test Plan > Subject > Sample(Folder Name) > Scenario (Sub Folder) > TC1 (Test Case ) 

How can i retrieve TC1 using OTA and Java. Written the following code to get the Test folders , but not able to get the test cases under the Scenario folder

ITreeManager iTreeManager = qcConnect.treeManager().queryInterface(ITreeManager.class);
ISubjectNode iSubNode = iTreeManager.nodeByPath("Subject\\Sample").queryInterface(ISubjectNode.class);
IList testFolders = iSubNode.newList();
  for (Com4jObject isys : testFolders) {
        System.out.println("Test folder : "+ isys.queryInterface(ISysTreeNode.class).());           
    }

How can I get to TC1 and update the fields in the test case

Once you get the ISubjectNode you want (the object that represents Test Plan folders), you can access the 'TestFactory' property of that folder to return a factory object that will let you access the tests stored in that folder.

I don't write Java, so here's my best attempt at what you need based on the code you provided:

// First access the TestFactory from the folder
ITestFactory iTestFact = iSubject.testFactory;

// Pull back a list of all tests.  Refer to OTA documentation on how to use filters on the list.
IList testList = iTestFact.newList();

// You can now iterate over the list of tests like you did subject folders