Unreolved Types IWorkItemWorkingCopyManager

I added the following code to the example JazzPlainJava code to try to do a work item updating instead of creating new one but can't compile the code as the following types can't resolved:
IWorkItemWorkingCopyManager, IComments, IComment.

I am new to Java, so where and how can I find out what lib/jar is missing?


IWorkItemWorkingCopyManager workingCopyManager = workItemClient.getWorkItemWorkingCopyManager();
IWorkItemHandle handle= workingCopyManager.connect(workItemType, null);
WorkItemWorkingCopy workingCopy = workingCopyManager.getWorkingCopy(handle);

// modify work item
IWorkItem myworkItem= workingCopy.getWorkItem();

IComments comments= myworkItem.getComments();
IComment comment= comments.createComment(teamRepository.loggedInContributor(), XMLString.createFromPlainText(description));
comments.append(comment);
workingCopy.save(null);