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