Hi All, We have an issue in rule when migrating drools from 3.0 to 5.1 with "eval". To demo this error, I use the following code: public class Info { public String getItem(int i) { return "item is " + i; } } In Drools 3.0, the following rule is fine: rule "test eval" salience 1 when info : Info() eval(into.getItem(0) != null) then System.out.println("test eval"); end But when using drools 5.1, it shows error "info can not be resolved". I found a way to resolve this issue but don't know this is the best practice. declare Item name : String end rule "insert item before eval" salience 0 when info : Info() then Item item = new Item(); item.setName(info.getItem(0)); insert( item ); end rule "test eval" salience 1 when item : Item(n : name) eval( n != null) then System.out.println("test eval"); end BTW, using "declare" in rule may cause memory leaking? We are seeing heap size growing after migrated to 5.1. Thanks, Liqun