String drl = "package org.drools.test; \n" +
"import org.drools.Person; \n " +
"global java.util.List list; \n" +
"\n" +
"\n" +
"rule TimeConsumingRule\n" +
"when \n" +
" $p : Person( $n : name ) \n" +
"then \n" +
" System.out.println( Thread.currentThread().getName() + \"Ill continue later \" ); \n" +
" Thread.sleep( 1000 ); \n" +
" System.out.println( Thread.currentThread().getName() + \"Hello >> \" + $n );\n" +
"end\n" +
"\n" +
"rule PreemptingRule\n" +
"timer( expr:0 )\n" +
"when\n" +
" $p : Person()\n" +
"then\n" +
" System.out.println( Thread.currentThread().getName() + \"Take out \" + $p ); \n" +
" retract( $p );\n" +
"end\n" +
"\n"
;

This particular test case throws a NPE when the accessor $n tries to read the - retracted - Person's name. The exception is not thrown when the time is > 0