Generate a String for a given size

How can I generate a String of a given size?

int someLimit = GlobalLimits.BULK_SIZE;

I want 3 Strings which satisfy the below conditions.

- RandomStr.length < someLimit.length

- RandomStr.length = someLimit.length

- RandomStr.length > someLimit.length

This is what I have tried so far.

private String getLowerRandomString(int upto){
  StringBuilder sBuilder = new StringBuilder();
  for (int i = 0; i < upto; i++){
    sBuilder.append("A");
  }

  return sBuilder.toString();
}

The problem what I see is, if my limit = 10000, it still loop up-to 9999 which is unnecessary. Share if you know a better approach than this. Thank you.

---

FYI: I was writing a unit test for a simple helper method.

public boolean isBulk(String text){
 int bulkLimit = ImportToolkit.getSizeLimit();
 if (text != null && text.length() > bulkLimit){
  return true;
 }
 return false;
}

So, I want to pass different sizes of strings as parameters to this method and want to assert whether it gives me expected results.