Extract a Wikipedia Page Directly from a Dump File with NLP4J
Wikipedia provides database dumps that are extremely useful for NLP, text mining, search, corpus construction, and knowledge-base development.
However, Wikipedia dump files are large, and extracting just one article from them is not always convenient.
I have added a small command-line tool to NLP4J that allows you to retrieve a Wikipedia page directly from a Wikipedia multistream dump by specifying its title.
For example:
java -jar nlp4j-wikipedia-app.jar \
--dump jawiki-20260801-pages-articles-multistream.xml.bz2 \
--index jawiki-20260801-pages-articles-multistream-index.txt.bz2 \
--title ドラゴンボール
This retrieves the Japanese Wikipedia page for ドラゴンボール (Dragon Ball) directly from the dump.
No database server or search server is required.
NLP4J
NLP4J is an open-source Java library for natural language processing and text analytics.
GitHub:
https://github.com/oyahiroki/nlp4j
The executable JAR used in this article is available here:
https://github.com/oyahiroki/nlp4j/blob/master/nlp4j/nlp4j-wiki/dist/nlp4j-wikipedia-app.jar
Downloading Wikipedia Dump Files
Wikipedia dump files are available from the official Wikimedia dump service.
For example, for the August 1, 2026 English Wikipedia dump, use:
https://dumps.wikimedia.org/enwiki/20260801/
As of August 2026, this directory contains the two files required by this tool: the combined multistream article dump and its corresponding index. (ウィキメディアダウンロード)
The files are:
enwiki-20260801-pages-articles-multistream.xml.bz2
enwiki-20260801-pages-articles-multistream-index.txt.bz2
The first file is the Wikipedia article dump:
enwiki-20260801-pages-articles-multistream.xml.bz2
The second file is the multistream index:
enwiki-20260801-pages-articles-multistream-index.txt.bz2
On August 11, 2026, Wikimedia listed these files as approximately 24.8 GB and 270.5 MB, respectively. (ウィキメディアダウンロード)
The Wikimedia page may still show:
Dump in progress
because other dump files are still being generated. However, the two multistream files above may already be marked as completed and can be downloaded. (ウィキメディアダウンロード)
English Wikipedia vs. Japanese Wikipedia
Wikipedia dump directory names include the language code.
For English Wikipedia:
enwiki
For Japanese Wikipedia:
jawiki
The command examples in this article use Japanese Wikipedia, so the corresponding files are:
jawiki-20260801-pages-articles-multistream.xml.bz2
jawiki-20260801-pages-articles-multistream-index.txt.bz2
For English Wikipedia, use the enwiki files instead.
This makes it easy to use the same NLP4J tool with different Wikipedia languages.
What You Need
The tool requires two files:
*-pages-articles-multistream.xml.bz2
*-pages-articles-multistream-index.txt.bz2
For the Japanese Wikipedia dump dated August 1, 2026:
jawiki-20260801-pages-articles-multistream.xml.bz2
jawiki-20260801-pages-articles-multistream-index.txt.bz2
The first file contains the Wikipedia pages.
The second file is the corresponding multistream index.
You do not need to decompress these .bz2 files before using the tool.
Basic Usage
The command syntax is:
java -jar nlp4j-wikipedia-app.jar \
--dump <Wikipedia dump file> \
--index <Wikipedia index file> \
--title <Wikipedia page title>
The options are:
| Option | Description |
|---|---|
--dump |
Wikipedia pages-articles-multistream.xml.bz2 file |
--index |
Wikipedia pages-articles-multistream-index.txt.bz2 file |
--title |
Title of the Wikipedia page to retrieve |
Example on Windows
I tested the following command on Windows:
java -jar nlp4j-wikipedia-app.jar --dump "C:\usr\local\wiki\jawiki\20260801\jawiki-20260801-pages-articles-multistream.xml.bz2" --index "C:\usr\local\wiki\jawiki\20260801\jawiki-20260801-pages-articles-multistream-index.txt.bz2" --title ドラゴンボール
The tool looks up the requested page in the multistream index and retrieves the corresponding page directly from the Wikipedia dump.
Another example is:
java -jar nlp4j-wikipedia-app.jar \
--dump "C:\usr\local\wiki\jawiki\20260801\jawiki-20260801-pages-articles-multistream.xml.bz2" \
--index "C:\usr\local\wiki\jawiki\20260801\jawiki-20260801-pages-articles-multistream-index.txt.bz2" \
--title 日本
This retrieves the Japanese Wikipedia page:
日本
Redirect the Result to a File
Because the page content is written to standard output, it can also be redirected to a file.
For example:
java -jar nlp4j-wikipedia-app.jar \
--dump "C:\usr\local\wiki\jawiki\20260801\jawiki-20260801-pages-articles-multistream.xml.bz2" \
--index "C:\usr\local\wiki\jawiki\20260801\jawiki-20260801-pages-articles-multistream-index.txt.bz2" \
--title ドラゴンボール \
> dragonball.txt
On Windows:
type dragonball.txt
On Linux or macOS:
cat dragonball.txt
The output contains the Wikipedia page data obtained directly from the dump.
This makes it easy to connect the tool with Java, Python, shell scripts, NLP tools, or text-mining pipelines.
Why Use the Multistream Index?
A Wikipedia pages-articles-multistream.xml.bz2 file contains a very large number of pages.
If we only want one particular page, processing the entire dump from the beginning would be inefficient.
Wikipedia also provides the corresponding multistream index:
pages-articles-multistream-index.txt.bz2
NLP4J uses this index to locate the requested article in the dump.
Conceptually, the operation is very simple:
Wikipedia title
|
v
Multistream index
|
v
Location in dump
|
v
Wikipedia page
For users of the command-line tool, this is hidden behind a simple option:
--title ドラゴンボール
Useful for NLP Experiments
Wikipedia dumps are frequently useful as source data for:
- NLP experiments
- text mining
- keyword extraction
- morphological analysis
- corpus construction
- search indexes
- knowledge bases
- entity analysis
- RAG data preparation
For many experiments, we do not need to process the entire Wikipedia dump immediately.
Sometimes we simply want to inspect a few specific pages first.
With nlp4j-wikipedia-app.jar, this can be done directly from the original compressed dump:
Wikipedia dump + index + page title
|
v
Wikipedia page
There is no need to import the dump into a database or search server just to retrieve one page.
Using It from Python
Since the tool is a normal command-line application, it can also be called from Python.
For example:
import subprocess
cmd = [
"java",
"-jar",
"nlp4j-wikipedia-app.jar",
"--dump",
r"C:\usr\local\wiki\jawiki\20260801\jawiki-20260801-pages-articles-multistream.xml.bz2",
"--index",
r"C:\usr\local\wiki\jawiki\20260801\jawiki-20260801-pages-articles-multistream-index.txt.bz2",
"--title",
"ドラゴンボール",
]
result = subprocess.run(
cmd,
capture_output=True,
text=True,
encoding="utf-8",
)
print(result.stdout)
The Wikipedia dump reader itself is implemented in Java, while it can still be incorporated easily into Python-based NLP workflows.
Summary
The NLP4J Wikipedia command-line tool provides a simple interface for retrieving individual Wikipedia pages directly from multistream dump files.
First, download the Wikipedia dump and index from Wikimedia.
For example, the August 1, 2026 English Wikipedia dump is available from:
https://dumps.wikimedia.org/enwiki/20260801/
Then run:
java -jar nlp4j-wikipedia-app.jar \
--dump <dump.xml.bz2> \
--index <index.txt.bz2> \
--title <Wikipedia title>
For Japanese Wikipedia:
java -jar nlp4j-wikipedia-app.jar \
--dump jawiki-20260801-pages-articles-multistream.xml.bz2 \
--index jawiki-20260801-pages-articles-multistream-index.txt.bz2 \
--title ドラゴンボール
The design goal is simple:
Use the original Wikipedia dump directly, without first building another database or search server.
For small experiments, corpus inspection, NLP development, and data preparation, being able to retrieve a Wikipedia page with a single command can be very useful.
Links
NLP4J:
https://github.com/oyahiroki/nlp4j
nlp4j-wikipedia-app.jar:
https://github.com/oyahiroki/nlp4j/blob/master/nlp4j/nlp4j-wiki/dist/nlp4j-wikipedia-app.jar
Wikimedia English Wikipedia dump, August 1, 2026: