Frequently Asked Questions

General Questions

I am getting the below Log4J warning message, how do I remove it?

log4j:WARN No appenders could be found for logger (org.apache.pdfbox.util.ResourceLoader).
log4j:WARN Please initialize the log4j system properly.

This message means that you need to configure the log4j logging system. See the log4j documentation for more information.

PDFBox comes with a sample log4j configuration file. To use it you set a system property like this

java -Dlog4j.configuration=log4j.xml org.apache.pdfbox.ExtractText <PDF-file> <output-text-file>

If this is not working for you then you may have to specify the log4j config file using a URL path, like this:

log4j.configuration=file:///<path to config file>

Is PDFBox thread safe?

No! Only one thread may access a single document at a time. You can have multiple threads each accessing their own PDDocument object.

Why do I get a "Warning: You did not close the PDF Document"?

You need to call close() on the PDDocument inside the finally block, if you don't then the document will not be closed properly. Also, you must close all PDDocument objects that get created. The following code creates two PDDocument objects; one from the "new PDDocument()" and the second by the load method.

PDDocument doc = new PDDocument();
try
{
doc = PDDocument.load( "my.pdf" );
}
finally
{
if( doc != null )
{
doc.close();
}
}

Font Handling

I'm getting java.lang.IllegalArgumentException: ... is not available in this font's encoding: WinAnsiEncoding

Check whether the character is available in WinAnsiEncoding by looking at the PDF Specification Appendix D. If not, but if it is available in this font (in windows, have a look with charmap.exe), then load the font with PDType0Font.load(), see also in the EmbeddedFonts.java example in the source code download.

PDF Creation

Can I use PDFBox to create complex layouts?

I'd like to use PDFBox to create a complex layout containing several paragraphs, tables, images etc. Is PDFBox fit for that purpose?

PDFBox being a low level PDF library provides the APIs to create page content such as text, images etc. But at this point in time it doesn't provide a higher level API to do page layout, paragraph handling, automatic line wrapping or create tables and such.

But PDFBox is the foundation of some projects which might help in that case. This includes projects such as

You may also want to consider using Apache FOP which allows to create complex documents from XML data and templates-

I'm creating a PDF but my page is empty. Why?

Make sure that you closed your content stream before saving.

Text Extraction

Why does the extracted text appear in the wrong sequence?

By default, text extraction is done in the same sequence as the text in the PDF page content stream. PDF is a graphic format, not a text format, and unlike HTML, it has no requirements that text one on page be rendered in a certain order. The order is the one that was determined by the software that created the PDF. To get text sorted from left to right and top to botton, use setSortByPosition(true).

How come I am not getting any text from the PDF document?

Text extraction from a pdf document is a complicated task and there are many factors involved that effect the possibility and accuracy of text extraction. It would be helpful to the PDFBox team if you could try a couple things.

How come I am getting gibberish(G38G43G36G51G5) when extracting text?

This is because the characters in a PDF document can use a custom encoding instead of unicode or ASCII. When you see gibberish text then it probably means that a meaningless internal encoding is being used. The only way to access the text is to use OCR. This may be a future enhancement.

What does "java.io.IOException: Can't handle font width" mean?

This probably means that the "Resources" directory is not in your classpath. The Resources directory is included in the PDFBox jar so this is only a problem if you are building PDFBox yourself and not using the binary.

Why do I get "You do not have permission to extract text" on some documents?

PDF documents have certain security permissions that can be applied to them and two passwords associated with them, an user password and an owner password. If the "cannot extract text" permission bit is set then you need to decrypt the document with the owner password in order to extract the text.

Can't we just extract the text without parsing the whole document or extract text as it is parsed?

Not really, for a couple reasons.

PDF rendering

I'm getting an OutOfMemoryError. What can I do?

The memory footprint depends on the PDF itself and on the resolution you use for rendering. Some possible options:

Why are some texts in poor quality and not antialiased?

This is because in some PDFs (e.g. the one in PDFBOX-2814, text is not rendered directly, but as a shaped clipping from a background. Java graphics does not support "soft clipping" https://bugs.openjdk.java.net/browse/JDK-4212743, and because of that, the edges are not looking smooth. Soft clipping could be achieved with some extra steps, but these would cost additional time and memory space. You can have a higher quality by rendering at a higher dpi and then downscale the image.

What to do with the IllegalArgumentException "Numbers of source Raster bands and source color space components do not match"?

Sadly, this is a known bug in Java Imaging. Use the twelvemonkeys library as described in the dependencies page.