• Extend to an External Class once; no multiple use of extends in Java
• Implement to an Interface; can have multiple implementation in Java

 
	package javatemplate1;
 public class JavaTemplate1 {
     // example of 
          public static void main(String[] args)  {
        System.out.println("main block executing");
        Process1 proc1 = new Process1();
         System.out.println("from ..."+ proc1.getClass());
         Process2 proc2 = new Process2();
         System.out.println("from ..."+proc2.getClass());
         System.out.println();
 }
 }
 // a class can extend once an ExternaClass
// a class can't implement another class but many interfaces
 class Process1 extends ExternalClass1{
public Process1(){
    System.out.println("The product :"+ proc1);
     System.out.println(  n1); 
   }
}
class Process2  implements Note1 {
    public Process2(){
     System.out.println("The product :"+proc1);
      System.out.println(  n1); 
    }
}
////ExternalClass1 

package javatemplate1;


 public class ExternalClass1 {
       String proc1 = "hello-class";
       int n1 = 13;  
}// external class 
// 
interface Note1
{
    String proc1 = "world-interface";
    int n1 = 14; 
}