Attaching external JARs to a java project in eclipse - java.lang.NoClassDefFoundError

Question

Trying to implement pdfbox in eclipse but I'm getting this error when I run it.

>Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory

>   at org.apache.pdfbox.pdfparser.BaseParser.<clinit>(BaseParser.java:68)

>   at com.pdf.util.PDFTextParser.<init>(PDFTextParser.java:26)

>   at com.pdf.util.PDFTextParser.main(PDFTextParser.java:77)

>Caused by: java.lang.ClassNotFoundException: org.apache.commons.logging.LogFactory

>   at java.net.URLClassLoader.findClass(Unknown Source)

>   at java.lang.ClassLoader.loadClass(Unknown Source)

>   at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)

>   at java.lang.ClassLoader.loadClass(Unknown Source)

>   ... 3 more

The program stops at this line of code:

parser = new PDFParser (new FileInputStream(file));

PDFParser comes from pdfbox.

I'm guessing there's something wrong with how I've attached the JAR files?

• I moved all the jar files to a folder I created called "lib" which is part of the project.
• Went into project Properties -> Java Build Path, and clicked "Add External JARs" for every JAR file
• After doing this I noticed that it said "Source attachment: none" for each of the JARs, so I clicked edit and set the destination to its location in the lib folder.
• When I go into Run Configuration, under Classpath, I can see the JAR files are there underneath my project.

Answer 1

PDFBox requires Commons Logging (see this dependencies page from the project's website). You need to reference that Jar in the classpath along with the PDFBox Jar. If you use a build tool like Maven, it should automatically download it for your project.

Answer 2

检查链接如何在堆栈溢出中将外部 jar 添加到类路径