I'm trying to create an accumulator to sum a BigDecimal. Here's what I wrote: $upcharge : BigDecimal( ) from accumulate( GroupUpcharges( row>$gb.row && row<=$gu.row, $value : upcharge), init( BigDecimal total = BigDecimal.ZERO; ), action( total=total.add($value); ), reverse( total=total.subtract($value); ), result( total ) ) $gb and $gu are set earlier in the WHEN clause. When I run this, it compiles successfully, but then flows up at run time with a null pointer exception. What am I doing wrong? -- View this message in context: http://drools.46999.n3.nabble.com/accumlator-and-BigDecimal-tp3185872p318... Sent from the Drools: User forum mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users