You must pass your ArrayList of object to jasper  as a JRBeanCollectionDataSource:

JRBeanCollectionDataSource ds = new JRBeanCollectionDataSource(list);
jasperPrint = JasperFillManager.fillReport(jr, reportParameters, ds);

Then in the JasperReport you refer to the object’s properties or methods, in an OGNL type manner. For example, to access the name property of an employee object within list objects, use:

employee.name

OR to reference a property called name within the list objects:

name