NullPointerException

[wangxiangtao]

Got the NullPointerException . How to solve it ?

public class OpenIETest {
public static void main(String a[])
{
OpenIE openie = new OpenIE(new ClearParser(new ClearPostagger(new ClearTokenizer())),new ClearSrl(),false,false);
System.out.println( openie.extract("The whales will not eat the otters"));

}

}