Selenium Element - selenium

Question

Not able to select a dynamic drop down PFB the html tag of the element.
Drop down dynamic ids:
page:frm:pageB:repeatUpper:0:repeat:1:ServiceSubtype
page:frm:pageB:repeatUpper:0:repeat:2:ServiceSubtype
HTML Code :
<td class="dataCell" style="border-top:1px solid #838282;">
<span id="page:frm:pageB:repeatUpper:0:repeat:1:DescPopup" class="DescServicePopupClone" style="display:none;"></span>
<span id="page:frm:pageB:repeatUpper:0:repeat:1:DescPopupHasResource" class="DescServicePopupHasResource" style="display:none;"></span>
<span id="page:frm:pageB:repeatUpper:0:repeat:1:DescPopupLOE" class="DescServicePopupLOE" style="display:none;"></span>
My code:
new Select(driver.findElement(By.xpath("//td[contains(#id, 'page:frm:pageB:repeatUpper:0:repeat:')]"))).selectByVisibleText("CAT-New Implementer");
Thread.sleep(18000);
getting the below error:
Caused by: org.openqa.selenium.NoSuchElementException: Unable to
locate element: {"method":"xpath","selector":"//td[contains(#id,
'page:frm:pageB:repeatUpper:0:repeat:')]"} For documentation on this
error, please visit:
http://seleniumhq.org/exceptions/no_such_element.html
UPDATE from OP - part of the "real" HTML:
<select id="page:frm:pageB:repeatUpper:0:repeat:2:ServiceSubtype" name="page:frm:pageB:repeatUpper:0:repeat:2:ServiceSubtype">
<option value="">--None--</option>
<option value="CAT-New Implementer">CAT-New Implementer</option>
<option value="CAT-Repeat Implementer">CAT-Repeat Implementer</option> </select> </span> </td>

Answer 1

Try this one:
new Select(driver.findElement(By.xpath("//select[starts-with(#id, 'page:frm:pageB:repeatUpper:0:repeat:')]"))).selectByVisibleText("CAT-New Implementer");
I also changed "contains" to "starts-with" because that better suits your example.

Answer 2

My suggestion to you is to not use XPath. Prefer ID, then maybe name, and then CSS Selectors. Those 3 locators should be 99% of your find methods. XPath is complex, fragile, and slow. Stick to the simple things until you get them mastered and then move on to XPath when you absolutely must.
This code should work
Select dropdown = new Select(driver.findElement(By.id("page:frm:pageB:repeatUpper:0:repeat:2:ServiceSubtype")));
dropdown.selectByVisibleText("CAT-New Implementer");
Since you have an ID on the SELECT, use that. Because it is a SELECT, casting the WebElement to a Select gets you extra options only available for SELECTs as far as choosing OPTIONs. For your example, you can use either .selectByVisibleText() or .selectByValue() since they are equivalent in the HTML you provided.
EDIT 1
Another option is to look for a partial ID, ID ends with ($) X, but I don't know if that is unique on your page.
Select dropdown = new Select(driver.findElement(By.cssSelector("span[id$=':ServiceSubtype']")));
Yet another option is to increment a counter and insert that into your ID string.
int i = 0;
Select dropdown2 = new Select(driver.findElement(By.id("page:frm:pageB:repeatUpper:0:repeat:" + i + ":ServiceSubtype")));
// i++; each time you add something