Don't need call to super class constructor

Hi, I have
class A {
public A() { System.out.println("in A()");}
public class B extends A
{ public B() {
System.out.println("in B()");}
public static void main( String args[] ) {
B b = new B();}
I don't want the super class constructor to be called... What to do? Please tell me solution other than usage of parameterised constructor?

I don't want the super class constructor to be called... What to do? Can't be done. One of the constructors of the super class must be invoked. (Implicitly or explicitly)
Kaj

Similar Messages

How to inherit super class constructor in the sub class

I have a class A and class B
Class B extends Class A {
// if i use super i can access the super classs variables and methods
// But how to inherit super class constructor
}

You cannot inherit constructors. You need to define all the ones you need in the subclass. You can then call the corresponding superclass constructor. e.g
public B() {
super();
public B(String name) {
super(name);
}

Can defualt inherited the Super Class constructor to sub class ?

Hi,
is it passible to inherit the super class constructor by defualt when extends the super class.
Thanks
MerlinRoshina

Constructor rules:
1) Every class has at least one ctor.
1.1) If you do not define an explicit constructor for your class, the compiler provides a implicit constructor that takes no args and simply calls super().
1.2) If you do define one or more explicit constructors, regardless of whether they take args, then the compiler no longer provides the implicit no-arg ctor. In this case, you must explicitly define a public MyClass() {...} if you want one.
1.3) Constructors are not inherited.
2) The first statement in the body of any ctor is either a call to a superclass ctor super(...) or a call to another ctor of this class this(...) 2.1) If you do not explicitly put a call to super(...) or this(...) as the first statement in a ctor that you define, then the compiler implicitly inserts a call to super's no-arg ctor super() as the first call. The implicitly called ctor is always super's no-arg ctor, regardless of whether the currently running ctor takes args.
2.2) There is always exactly one call to either super(...) or this(...) in each constructor, and it is always the first call. You can't put in more than one, and if you put one in, the compiler's implicitly provided one is removed.

Is it possible to override super class constructor?

Is it possible to override super class constructor form subclass?

However, you can achieve do something that looks similar to overriding.
class Parent {
Parent(int i, String s) {
    // do stuff
class Child extends Parent {
Child(int i, String s) {
    super(i, s);
    // do Child stuff here
new Parent(1, "abc");
new Child(2, "xyz");Although that's not overriding, it sort of looks similar. Is this what you were talking about?

Error while calling a super class public method in the subclass constructor

Hi ,
I have code like this:
CLASS gacl_applog DEFINITION ABSTRACT.
PUBLIC SECTION.
    METHODS:
            create_new_a
               IMPORTING pf_obj       TYPE balobj_d
                          pf_subobj    TYPE balsubobj
                          pf_extnumber TYPE string
               EXPORTING pfx_log_hndl TYPE balloghndl
               EXCEPTIONS error
ENDCLASS.
CLASS gacl_applog IMPLEMENTATION.
METHOD create_new_a.
    DATA: ls_log TYPE bal_s_log.
Header aufsetzen
    MOVE pf_extnumber TO ls_log-extnumber.
    ls_log-object     = pf_obj.
    ls_log-subobject = pf_subobj.
    ls_log-aluser     = sy-uname.
    ls_log-alprog     = sy-repid.
    ls_log-aldate     = sy-datum.
    ls_log-altime     = sy-uzeit.
    ls_log-aldate_del = ls_log-aldate + 1.
    CALL FUNCTION 'BAL_LOG_CREATE'
         EXPORTING
              i_s_log      = ls_log
         IMPORTING
              e_log_handle = pfx_log_hndl
         EXCEPTIONS
              OTHERS       = 1.
    IF ( sy-subrc NE 0 ).
      MESSAGE ID      sy-msgid TYPE sy-msgty NUMBER sy-msgno
              WITH    sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4
              RAISING error.
    ENDIF.
ENDMETHOD.
CLASS gcl_applog_temp DEFINITION INHERITING FROM gacl_applog.
PUBLIC SECTION.
    DATA: log_hndl   TYPE balloghndl READ-ONLY
        , t_log_hndl TYPE bal_t_logh READ-ONLY
    METHODS: constructor
               IMPORTING pf_obj       TYPE balobj_d
                          pf_subobj    TYPE balsubobj
                          pf_extnumber TYPE string
               EXCEPTIONS error
           , msg_add      REDEFINITION
           , display      REDEFINITION
ENDCLASS.
CLASS gcl_applog_temp IMPLEMENTATION.
METHOD constructor.
    CALL METHOD create_new_a
           EXPORTING pf_obj       = pf_obj
                      pf_subobj    = pf_subobj
                      pf_extnumber = pf_extnumber
           IMPORTING pfx_log_hndl = log_hndl.
    IF ( sy-subrc NE 0 ).
      MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
              WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4
              RAISING error.
    ENDIF.
ENDMETHOD.
A public method of Super class has been called from the constructor of the sub class. we are getting the syntax error :
' In the constructor method, you can only access instance attributes, instance methods, or "ME" after calling the constructor of the superclass'
Can you please suggest how to change the code with out affecting the functioanlity.
Thank you ,
Lakshmi.

Hi,
Call that method by instance of Subclass.   OR
SUPER-->method.
Read very useful document
Constructors
Constructors are special methods that cannot be called using CALL METHOD. Instead, they are called automatically by the system to set the starting state of a new object or class. There are two types of constructors - instance constructors and static constructors. Constructors are methods with a predefined name. To use them, you must declare them explicitly in the class.
The instance constructor of a class is the predefined instance method CONSTRUCTOR. You declare it in the public section as follows:
METHODS CONSTRUCTOR
        IMPORTING.. [VALUE(]<ii>[)] TYPE type [OPTIONAL]..
        EXCEPTIONS.. <ei>.
and implement it in the implementation section like any other method. The system calls the instance constructor once for each instance of the class, directly after the object has been created in the CREATE OBJECT statement. You can pass the input parameters of the instance constructor and handle its exceptions using the EXPORTING and EXCEPTIONS additions in the CREATE OBJECT statement.
The static constructor of a class is the predefined static method CLASS_CONSTRUCTOR. You declare it in the public section as follows:
CLASS-METHODS CLASS_CONSTRUCTOR.
and implement it in the implementation section like any other method. The static constructor has no parameters. The system calls the static constructor once for each class, before the class is accessed for the first time. The static constructor cannot therefore access the components of its own class.
Pls. reward if useful....

Invoked super class constructor means create an object of it?

Hei,
i have create one class that extends another class. when i am creating an object of sub class it invoked the constructor of the super class. thats okay.
but my question is :
constructor is invoked when class is intitiated means when we create an
object of sub class it automatically create an object of super class. so means every time it create super class object.

Hi,
   An object has the fields of its own class plus all fields of its parent class, grandparent class, all the way up to the root class Object. It's necessary to initialize all fields, therefore all constructors must be called! The Java compiler automatically inserts the necessary constructor calls in the process of constructor chaining, or you can do it explicitly.
   The Java compiler inserts a call to the parent constructor (super) if you don't have a constructor call as the first statement of you constructor.
Normally, you won't need to call the constructor for your parent class because it's automatically generated, but there are two cases where this is necessary.
   1. You want to call a parent constructor which has parameters (the automatically generated super constructor call has no parameters).
   2. There is no parameterless parent constructor because only constructors with parameters are defined in the parent class.
   I hope your query is resolved. If not please let me know.
Thanks & Regards,
Charan.

Invoke super class constructor of super class' parent class

I would like to invoke a constructor of a super class that is the parent of the direct super class. For instance:
class C extends class B, and class B extends class A.
From class C, is it possible to invoke class A's constructor without first invoking class B constructor?
Something like super.A() ??
Thanks.
Joe

try this,
abstract class GrandParent
      private Object pObj = null;
      protected Via via = new Via();
      protected class Via
         public Object doMethod1( Object obj )
            pObj = obj;
            return "GrandParent m1: " + pObj;
         public Object doMethod2( Object obj )
            pObj = obj;
            return "GrandParent m2: " + pObj;
         public Object get()
            return "gp get: " + pObj;
      public abstract Object doMethod1( Object obj );
      public abstract Object doMethod2( Object obj );
      public abstract Object get();
class Parent extends GrandParent
      private Object pObj = null;
      public Object doMethod1( Object obj )
      pObj = obj;
      return "Parent m1: " + pObj;
      public Object doMethod2( Object obj )
      pObj = obj;
      return "Parent m2: " + pObj;
      public Object get()
      return "p get: " + pObj;
public class GPMethod extends Parent
      public static void main( String[] args )
      GrandParent gp = new Parent();
      System.out.println( gp.doMethod1( "calling parent" ) );
      System.out.println( gp.doMethod2( "calling parent m2" ) );
      System.out.println( gp.get() );
      System.out.println( "" );
      System.out.println( gp.via.doMethod1( "calling via to GP" ) );
      System.out.println( gp.via.doMethod2( "calling via to GP m2" ) );
      System.out.println( gp.via.get() );
}

Calling the super class method from the subclass

Hi all,
I have a question about inheritence and redefinition of methods. Is it possible to call the superclass implementation of a method which is redefined in the subclass in another method of the subclass?There are possbilities like creation of an explicit super class instance or delegating the super class method implementation to another method which is also protected etc. What i mean is, is there a direct way of calling it?We have ,me, as the reference for the instance we have(which is the subclass instance in this case), is there also a way of pointing the superclass implementation(with super we can reference in the subclass redefinition, my question is if we have such a parameter in other methods of the subclass too)
Thanks in advance
Sukru

Hi,
The super reference can only be used in redefined methods to call superclass implementation . So probably what you can do is use upcasting and access the required superclass implementation. I can think of only this way...;-)
Ex data lr_super type ref to cl_superclass
lr_super = lr_subclass.
lr_super->method().
~Piyush Patil

Using super class constructor in subclass constructor

Hi all. How can I use Person() in my Client()?
something like this:
public class Client extends Person{
      private float balance;
      Client(String firstName,String midleName,String lastName,Contacts contacts,Adress adress,float balance){
           this= Person(firstName,midleName,lastName,contacts,adress);
           this.balance=balance;
      }

public class Client extends Person{
private float balance; // float?!? Are you sure.... ?
Client(String firstName,String midleName,String lastName,Contacts contacts,Adress adress,float balance){
    super(firstName,midleName,lastName,contacts,adress);
    this.balance=balance;
}

Calling overideen method in constructor

Hi ,
I want to know why is the overiden method of subclass is called from super class constructor,below is the code
import java.util.*;
class Super{
     // Broken - constructor invokes an overridable method
     public Super(){
          overrideMe();
     public void overrideMe(){
          System.out.println( " in overide me of super class" );
public final class Sub extends Super{
     private final Date date; // Blank final, set by constructor
     Sub(){
          date = new Date();
     // Overriding method invoked by superclass constructor
     @Override
     public void overrideMe(){
          System.out.println( " in overide me of subclass" );
          System.out.println( date );
     public static void main( String[] args ){
          Sub sub = new Sub();
          sub.overrideMe();
}

Vicky wrote:
My question is still unaswered Y is the overideen method of subclass called when subclass object is not created at allAs EJP already told you:
1. This is false.
2. There is only a single object. There are NOT separate Super/Sub objects. Always. Even after all construction has completed.
That object has everything defined in the superclass and everything defined in the subclass. The subclass's constructor has not yet run, but that doesn't matter. Constructors don't create objects. They only initialize newly created objects to valid states. So we have a single object, with all the Super's fields and all the Sub's fields. The Sub's fields still have their default values (0/false/null). That's all. Polymorphism still works like it always does.
and even there is no reference of subclass tooFalse.
There is one object. It IS-A Super and it IS-A Sub. The "this" reference points to it, so when we call foo(), which is equivalent to this.foo(), we are traversing the "this" reference to get to the single Super/Sub object and call Sub's overriding implementation of foo() if it's present, or super's implementation if it's not overridden.
and also i have another question creating a object of a subclass does it also means creating an object of super class and subclass ?Having read the above, you now know the answer to this.

Even i call this() paramerterised constuctor in my class, Is super class su

Even i call this() paramerterised constuctor in my class, Is super class super() parameter less constuctor invokes?
I have excuted the following program. And result will be as follows:
Grandparent() constructor
Parent 25 constructor
Parent() constructor
Child() constructor
The program is below:
class ConstructorChain {
public static void main(String[] args) {
Child c = new Child();
class Child extends Parent {
Child() {
System.out.println("Child() constructor");
class Parent extends Grandparent {
Parent() {
this(25);
System.out.println("Parent() constructor");
Parent(int x) {
System.out.println("Parent(" + x + ") constructor");
class Grandparent {
Grandparent() {
System.out.println("Grandparent() constructor");
for this my excepected answer is
Parent 25 constructor
Parent() constructor
Child() constructor
because in parent class i defined this() constructor so, as my undersatnd is it never call Grand Parent Constructor as it is default parameterless constructor.
please Advise me
Aruna

You can't initialize a class without it's super classes constructor being run. So even if you call another constructor (of the same class), the parent classes constructor will still be called.

Reference to enclosing instance in inner class constructor

Is there any Java compiler which assigns reference to enclosing instance in constructor of inner clase before invoking super class constructor?
class Outer {
class Inner extends Global {
public Inner(int x) {
// I want (Outer.this != null) here
super();
class Global {
public Global(int x) {

class Outer {
class Inner extends Global {
public Inner(int x) {
// I want (Outer.this != null) hereOuter.this is never null at this point. A non-static
inner class always has an implicit reference to an
instance of the enclosing class.Try this:
class Outer {
int m;
class Inner extends Global {
public Inner(int x) {
super(x);
protected void init(int x) {
xxx = Outer.this.m + x; // Null pointer exception!!!
class Global {
int xxx;
public Global(int x) {
init(x);
protected void init(int x) {
xxx = x;

Regarding Super classes

Hi,
I have created one class in SE24. This class will be used as a super class for other classes.
When subclasses are derived from this superclass, i want to make sure that some of the methods of superclasses are redefined by the subclasse compulsarily.
So i want to force the subclasses to redefine complusarily some of the methods of its super class.
Is this feasible. If so please let me know the corresponding approach.
Thanks in advance !
Pramod

Hi,
Check this out this will help you.
Inheritance is the concept of passing the behavior of a class to another class.
1.You can use an existing class to derive a new class.
2.Derived class inherits the data and methods of a super class.
3.However they can overwrite the methods existing methods and also add new once.
4.Inheritance is to inherit the attributes and methods from a parent class.
Inheritance:
Inheritance is the process by which object of one class acquire the properties of another class.
Advantage of this property is reusability.
This means we can add additional features to an existing class with out modifying it.
Go to SE38.
Provide the program name.
Provide the properties.
Save it.
Provide the logic for inheritance.
*& Report ZLOCALCLASS_VARIABLES                      *
*&----------------------------------------------------*REPORT ZLOCALCLASS_VARIABLES.
*OOPS INHERITANCE
*SUPER CLASS FUNCTIONALITY
*DEFINE THE CLASS.
CLASS CL_LC DEFINITION.
PUBLIC SECTION.
DATA: A TYPE I,
      B TYPE I,
      C TYPE I.
METHODS: DISPLAY,
         MM1.
CLASS-METHODS: MM2.
ENDCLASS.
*CLASS IMPLEMENTATION
CLASS CL_LC IMPLEMENTATION.
METHOD DISPLAY.
WRITE:/ 'THIS IS SUPER CLASS' COLOR 7.
ENDMETHOD.
METHOD MM1.
WRITE:/ 'THIS IS MM1 METHOD IN SUPER CLASS'.
ENDMETHOD.
METHOD MM2.
WRITE:/ 'THIS IS THE STATIC METHOD' COLOR 2.
WRITE:/ 'THIS IS MM2 METHOD IN SUPER CLASS' COLOR 2.
ENDMETHOD.
ENDCLASS.
*SUB CLASS FUNCTIONALITY
*CREATE THE CLASS.
*INHERITING THE SUPER CLASS.
CLASS CL_SUB DEFINITION INHERITING FROM CL_LC. "HOW WE CAN INHERIT
PUBLIC SECTION.
DATA: A1 TYPE I,
      B1 TYPE I,
      C1 TYPE I.
METHODS: DISPLAY REDEFINITION,     "REDEFINE THE SUPER CLASS METHOD
         SUB.
ENDCLASS.
*CLASS IMPLEMENTATION.
CLASS CL_SUB IMPLEMENTATION.
METHOD DISPLAY.
WRITE:/ 'THIS IS THE SUB CLASS OVERWRITE METHOD' COLOR 3.
ENDMETHOD.
METHOD SUB.
WRITE:/ 'THIS IS THE SUB CLASS METHOD' COLOR 3.
ENDMETHOD.
ENDCLASS.
*CREATE THE OBJECT FOR SUB CLASS.
DATA: OBJ TYPE REF TO CL_SUB.
START-OF-SELECTION.
CREATE OBJECT OBJ.
CALL METHOD OBJ->DISPLAY. "THIS IS SUB CLASS METHOD
CALL METHOD OBJ->SUB.
WRITE:/'THIS IS THE SUPER CLASS METHODS CALLED BY THE SUB CLASS OBJECT'COLOR 5.
SKIP 1.
CALL METHOD OBJ->MM1.     "THIS IS SUPER CLASS METHOD
CALL METHOD OBJ->MM2.
*CREATE THE OBJECT FOR SUPER CLASS.
DATA: OBJ1 TYPE REF TO CL_LC.
START-OF-SELECTION.
CREATE OBJECT OBJ1.
SKIP 3.
WRITE:/ 'WE CAN CALL ONLY SUPER CLASS METHODS BY USING SUPER CLASS OBJECT' COLOR 5.
CALL METHOD OBJ1->DISPLAY. "THIS IS SUPER CLASS METHOD
CALL METHOD OBJ1->MM1.
CALL METHOD OBJ1->MM2.
This example will help you to solve your problem.
For more detailed information GOTO -> SAPTECHNICAL ->Tutorials -> Object Oriented Programming.
Regards Madhu.
Code Formatted by: Alvaro Tejada Galindo on Jan 7, 2009 12:13 PM

Calling constructor of super class

Hello everyone! I'm a student. I hope I can find guidance. Here's the issue:
Super class: Property
Sub class: House
constructor of parent class:
protected Property(String id, char status, String address,
        String tenet, String landlord, long rent, char freq,
        long amtDue, String date, boolean repair, char tradesman)
        this.id = id;
        this.status = status;
        this.address = address;
        this.tenet = tenet;
        this.landlord = landlord;
        this.rent = rent;
        this.freq = freq;
        this.amtDue = amtDue;
        this.repair = repair;
        this.tradesman = tradesman;
        SimpleDateFormat formatter = new SimpleDateFormat("dd.MM.yy");
        this.dateDue = formatter.parse(date, new ParsePosition(0));
    }the constuctor of the sub class:
public House(String id, char status, String address,
        String tenet, String landlord, long rent, char freq,
        long amtDue, String dateDue, boolean repair, char tradesman,
        int broom, int proom, int throom, boolean garden,
        boolean garage, boolean heating)
    super(id, status, address, tenet, landlord, rent, freq,
        amtDue, dateDue, repair, tradesman);
    this.broom = broom;
    this.proom = proom;
    this.throom = throom;
    this.garden = garden;
    this.garage = garage;
    this.heating = heating;
    }I'm sure you notice I'm calling the constructor of the Property in House. That;s where the error is when i try to compile either class. This is the error it shows within the House class.
Object() in java.lang.Object cannot be applied to (java.lang.String,char,java.lang.String,java.lang.String,java.lang.String,long,char,long,java.lang.String,boolean,char)
Maybe its elementary? Thanks in advance..

You haven't pasted all the code so I can only guess that the class House does not extend Property class.
public class House extends Property
// put the constructor here
}If the House class does not extend Property (or any other class) it just extends (by default) the Object class, which does not have the constructor of Property class.
Hope it helps
Nick

Constructor of derived-class has to call constructor of super-class?

In java, constructor of derived-class has to call constructor of super-class? there is no way to omit this step?

Correct. If you do not explicitly call the constructor, a call to the no-arg c'tor, super(), is automatically inserted.
It would be a mess to have it any other way. You'd be creating objects that are not completely initialized. They'd be in an invalid state.
Constructor rules:
1) Every class has at least one ctor.
1.1) If you do not define an explicit constructor for your class, the compiler provides a implicit constructor that takes no args and simply calls super().
1.2) If you do define one or more explicit constructors, regardless of whether they take args, then the compiler no longer provides the implicit no-arg ctor. In this case, you must explicitly define a public MyClass() {...} if you want one.
1.3) Constructors are not inherited.
2) The first statement in the body of any ctor is either a call to a superclass ctor super(...) or a call to another ctor of this class this(...) 2.1) If you do not explicitly put a call to super(...) or this(...) as the first statement in a ctor that you define, then the compiler implicitly inserts a call to super's no-arg ctor super() as the first call. The implicitly called ctor is always super's no-arg ctor, regardless of whether the currently running ctor takes args.
2.2) There is always exactly one call to either super(...) or this(...) in each constructor, and it is always the first call. You can't put in more than one, and if you put one in, the compiler's implicitly provided one is removed.

Don't need call to super class constructor

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