Java class implementing an interface and another class extending this class -

i have java interface has few abstract methods.

public interface interface {     void test();     void test1(); } 

now have class implements interface. requirement want extend class multiple client classes. class should implement test(). want class should keep test1 abstract , implementation of test1 should done in clients of class a. possible achieve in java. if yes, can correct way implement requirement ?

first of all, every method interface public , abstract default. have no choice.

here's how i'd write it, better names:

public interface {     void test1();     void test2(); }  public abstract class b implements { {     public void test1() { // here; concrete implementation }     // note: nothing test2.       // compiler doesn't complain because it's abstract class, , abstract method. }  public class c extends b {     // note: nothing test1 - abstract superclass     // note: compiler complain if nothing done implement test2(), because c isn't abstract     public void test2() { // here; concrete implementation } } 

class c can override test1() if chooses to, if nothing done it'll inherit behavior specified in class b.