Erreur java

public class aa {
private String mot;
private String def; 
public aa(String mot,String def){
 this.mot=new String(mot);
 this.def=new String(def);
 
}
public void decomposer(String mot)  {
 System.out.println(mot.length());
}
    public static void main(String[] args) {
     
     // TODO, add your application code
     System.out.println("Hello World!");
     aa a=new aa("xxxxx","xxxxxx");
     a.decomposer("hello xxxxx xxxxxxxx");
    }
}