hi , i am getting this error in main while making a wsdl project java.lang.NoClassDefFoundError

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Logger
at com.eviware.soapui.impl.wsdl.AbstractTestPropertyHolderWsdlModelItem.<clinit>(AbstractTestPropertyHolderWsdlModelItem.java:34)
at WsdlAnalyzer.main(WsdlAnalyzer.java:12)
Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Logger
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown So