Whenever i want to fill my report in my java class, i am getting this error : java.lang.NoClassDefFoundError: org/apache/commons/collections/ReferenceMap at net.sf.jasperreports.engine.design.JRAbstractJavaCompiler.<clinit>(JRAbstractJavaCompiler.java:58) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) All the classes that comes with ireports are in classpath. Please help it is very urgent.