Selenium - Get all cells under column header

silver :

Trying to get all td (cells) under a specific th (header)

HTML:

<table width="800">
    <tbody>
        <tr>
            <th><b>User ID</b></th>
            <th><b>Workforce ID</b></th>
            <th><b>Given Name</b></th>
            <th><b>Surname</b></th>
            <th><b>Division</b></th>
            <th><b>Hire Date</b></th>
            <th><b>Department</b></th>
            <th><b>emplType</b></th>
            <th><b>Associations</b></th>
            <th><b>SAP Roles</b></th>
            <th><b>Community</b></th>
            <th><b>Active</b></th>
        </tr>
        <tr>
            <td class="active"><a href="?username=utest001">utest001</a></td>
            <td class="active">00700001</td>
            <td class="active">User</td>
            <td class="active">Test001</td>
            <td class="active">Coles</td>
            <td class="active">2015-10-27</td>
            <td class="active">CHFITVB</td>
            <td class="active">S</td>
            <td class="active">IAM</td>
            <td class="active"></td>
            <td class="active">Workforce</td>
            <td class="active">Y</td>
        </tr>
        <tr>
            <td class="disabled"><a href="?username=utest002">utest002</a></td>
            <td class="disabled">00700002</td>
            <td class="disabled">Vasia</td>
            <td class="disabled">Smith</td>
            <td class="disabled">Coles</td>
            <td class="disabled">2015-11-16</td>
            <td class="disabled">C0584SV</td>
            <td class="disabled">W</td>
            <td class="disabled"></td>
            <td class="disabled"></td>
            <td class="disabled">Workforce</td>
            <td class="disabled">N</td>
        </tr>
    </tbody>
</table>

Method:

public List<WebElement> getCellsUnderHeader(WebElement table, String headerName) {
    List<WebElement> thList = table.findElements(By.cssSelector("th > b"));
    List<String> headers = new ArrayList<>();
    thList.stream().forEach(th -> headers.add(th.getText()));
    int index = headers.indexOf(headerName);
    List<WebElement> trList = table.findElements(By.tagName("tr"));
    List<WebElement> tdList = new ArrayList<>();
    List<WebElement> columnCells = new ArrayList<>();
    WebElement cell = null;
    for (WebElement tr : trList) {
        tdList = tr.findElements(By.tagName("td"));
        cell = tdList.get(index); // Getting out of bounds here
        columnCells.add(cell);
    }
    return columnCells;
}

Actual Result:

java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0

Expected Result:

Return a List<WebElement> containing 2 td (with a tag) under header User ID.

Guy :

trList contains the <tr> with the headers, which doesn't have <td> tags so in the first for iteration tdList is empty and tdList.get(index) throws IndexOutOfBoundsException.

You can iterate by index instead

for (int i = 1 ; i < trList.size() ; i++) {
    tdList = trList.get(i).findElements(By.tagName("td"));
    cell = tdList.get(index);
    columnCells.add(cell);
}

Or ship first item

for (WebElement tr : trList.subList(1, trList.size())) {
    tdList = tr.findElements(By.tagName("td"));
    cell = tdList.get(index);
    columnCells.add(cell);
}