How to modify Google Docs content using Java API client library

Other Questions Google docs
1

I’m working on a Java application that needs to modify existing Google Docs files. I’ve successfully implemented document creation and deletion features, but I’m stuck on the content modification part.

public void modifyDocument() throws IOException {
    ByteArrayInputStream contentStream = new ByteArrayInputStream("UPDATED TEXT".getBytes("UTF-8"));
    InputStreamContent streamContent = new InputStreamContent();
    streamContent.inputStream = contentStream;
    streamContent.type = "text/plain";

    HttpRequest httpReq = transport.buildPostRequest();
    httpReq.setUrl("https://docs.google.com/feeds/default/media/document:0B[example]7Z");
    httpReq.content = streamContent;

    // httpReq.headers.set("If-Match", "*");

    try {
        httpReq.execute().parseAs(DocumentListEntry.class);
    } catch (HttpResponseException ex) {
        if (DEBUG_MODE) Log.d(LOG_TAG, "HTTP error: " + ex.response.parseAsString());
        throw ex;
    } catch (ClientProtocolException ex) {
        if (DEBUG_MODE) Log.d(LOG_TAG, "Protocol error: " + ex.getMessage());
        throw ex;
    }
}

When I run this code without the If-Match header, it creates a new document instead of updating the existing one. But when I include the If-Match header, I get this error:

11-19 12:30:45.123: DEBUG/GoogleAPI(12345): HTTP Error Response:
<errors xmlns='http://schemas.google.com/g/2005'>
<error>
<domain>GData</domain>
<code>noPostConcurrency</code>
<internalReason>POST method does not support concurrency</internalReason>
</error>
</errors>
501 Not Implemented

What’s the correct approach to update document content using the Google API Java client? Am I using the wrong HTTP method or missing some required parameters?

2

I ran into something very similar when integrating Google Docs editing into our enterprise application. The error you’re seeing indicates you’re hitting an outdated endpoint that doesn’t support the operations you’re trying to perform.

From my experience, the key issue is that you cannot simply replace document content with a plain text stream like you would with a regular file upload. Google Docs maintains complex formatting and structure that gets corrupted when you try to overwrite it directly. What worked for me was switching to the Documents API v1 and using structured operations.

Instead of trying to replace entire content, you need to work with specific text ranges and use operations like replaceAllText or insertText with proper start and end indices. The authentication mechanism also changed significantly - make sure you’re using the newer OAuth2 flow rather than deprecated credential methods. Once I made these adjustments, the concurrency errors disappeared and updates worked reliably across multiple document types.

3

The issue you’re encountering stems from using the deprecated Google Documents List API. That API was shut down in 2012 and replaced with the Google Docs API v1. Your current approach with direct HTTP requests to the feeds endpoint won’t work anymore.

I migrated a similar Java application last year and found that switching to the modern Google Docs API resolved these exact errors. You’ll need to use the batchUpdate method instead of trying to POST content directly. The new API requires you to specify precise operations like inserting text at specific indices or replacing ranges of content.

First, add the current Google Docs API dependency to your project, then use the Docs.documents().batchUpdate() method with properly structured requests. The authentication flow is also different now - you’ll need to use OAuth2 credentials rather than the old client login method. The transition requires some refactoring but the API is much more reliable and gives you granular control over document modifications.

4

yeah you’re definietly using the wrong api there. that gdata endpoint hasnt worked in years - google killed it ages ago. you need to switch to the docs api v1 and use batchUpdate requests instead of trying to post raw content like that.