The following rules

package org.drools.compiler.loop

rule "Rule 1"
  ruleflow-group "Start"
  no-loop
  when
  	$thing1 : String()
	$thing2 : Integer()
  then
    System.out.println( 'At 1' );
	update( $thing2 );
end

rule "Rule 2"
  ruleflow-group "End"
  no-loop
  when
  	$thing1 : String()
  	$thing2 : Integer()
  then
    System.out.println( 'At 2' );
  	update( $thing2 );
end

cause an endless loop even if controlled by a jBPM process with two rule tasks