java中如何初始化接口

 chart.setBackgroundImageAlpha(Paint.OPAQUE);

   public interface RandVals {  
    int rint = (int)(Math.random() * 10);  
    long rlong = (long)(Math.random() * 10);  
    float rfloat = (float)(Math.random() * 10);  
    double rdouble = Math.random() * 10;  
   } ///:~  

   //: TestRandVals.java  
   public class TestRandVals {  
    public static void main(String[] args) {  
       System.out.println(RandVals.rint);  
       System.out.println(RandVals.rlong);  
       System.out.println(RandVals.rfloat);  
       System.out.println(RandVals.rdouble);  
    }  
   } ///:~