How to populate Google Sheets via API in Java
<p>I have a 3 column Spreadsheet [Date, Time, Subject] that I want to populate via the Sheets API using Java.</p>

<p>I understand how to read rows:</p>

<pre><code>    for (List row : values)
        System.out.println(row.get(0) + row.get(1) + row.get(2));
</code></pre>

<p>But I am having trouble using their documentation to understand <strong>how to insert specific strings into specific rows and columns</strong>. I know there exists a method <code>row.set(int index, Object element)</code> but when I try to insert a new row like this:</p>

<pre><code>    for (List row : values)
    {
        row.set(0, message.full_date);
        row.set(1, message.time);
        row.set(2, message.subject);
    }
</code></pre>

<p>nothing is updating in my sheets. My full code:</p>

<pre><code>private static void Update_Sheets(Sheets sheets_service, GmailMessage message) throws IOException
    {
        String spreadsheetId = id;

        String range = "Sheet1!A1:C2";
        ValueRange response = sheets_service.spreadsheets().values()
                .get(spreadsheetId, range)
                .execute();
        List&lt;List&lt;Object&gt;&gt; values = response.getValues();

        for (List row : values)
        {
            row.set(0, message.full_date); //a string
            row.set(1, message.time);      //a string
            row.set(2, message.subject);   //a string
        }
    }
</code></pre>