[rules-users] help! rule"rule_key" failed to predicate

hello,everyone! I wrote a rule with Drools, I compile the program and get the errors as follows: [3,0]: [ERR 103] Line 3:0 rule 'rule_key' failed predicate: {(validateIdentifierKey(DroolsSoftKeywords.RULE))}? in rule [3,9]: [ERR 101] Line 3:9 no viable alternative at input 'com' in rule package [7,0]: [ERR 101] Line 7:0 no viable alternative at input 'import' in rule package in rule sample I don't know how it happened, looking forward to your reply! thank you !!! PS: My rules are here: dialect "mvel" package com.sample import com.sample.Server; rule "system will execute 'tc' command" when eval(Server.Message>8388608) then System.out.println("The network is so crowd that it needs repairing."); Runtime.getRuntime().exec("tc");#give the authority and execute the "tc" command end rule "caution" when eval(Server.Message==8388608) then System.out.println("caution!The network maybe will get blocked very soon."); end rule "fluent network" when eval(Server.Message<8388608)#conditions then System.out.println("the current network is very good");#actions end