Multiple inheritance (cannot reference name before supertype constructor has been called)

[deepu bhadriraju]

//Grand Parent class
public class ConstructChaining {
    
    String name;
  public  int dd;
   public int mm;
    public int yyyy;

    public ConstructChaining(String name, int dd, int mm, int yyyy) {
        this.name = name;
        this.dd = dd;
        this.mm = mm;
        this.yyyy = yyyy;
    }
    
    public void  dispDetails()
    {
    System.out.println("name\t"+name);
    System.out.println("dd\t"+dd);
    System.out.println("mm\t"+mm);
    System.out.println("yyyy\t"+yyyy);
    
    }
    
    
}

//parent class
public class ConstructChain2 extends ConstructChaining {
    int salary;

    public ConstructChain2(String name, int dd, int mm, int yyyy, int salary) {
        super(name, dd, mm, yyyy);
        this.salary = salary;
    }
   
    @Override
    public void dispDetails(){
    super.dispDetails();
    System.out.println("salary\t"+salary);

            
    
}
}


//Child Class
public class Trainee  extends ConstructChain2{
    int m1,m2,m3;

    public Trainee(int m1, int m2, int m3)
    {
           super(name, dd, mm, yyyy,salary);
        this.m1 = m1;
        this.m2 = m2;
        this.m3 = m3;
    }
    
    
    public char GPA()
    {
        float avg;
        avg=(this.m1+this.m2+this.m3)/3;
        if(avg>70) return 'A';
        else if(avg>60) return 'B';
        else return 'C';
        
    }
}

[Added code tags - see UseCodeTags for details]

please help me out
I am getting the error in child class class constructor i.e in super(name,dd,mm,yyyy,salary)
cannot reference name before supertype constructor has been called
cannot reference dd before supertype constructor has been called
cannot reference mmbefore supertype constructor has been called
cannot reference yyyy before supertype constructor has been called

[Seetharaman Venkatasamy]

Let's take this example which is simplified version of your problem

class VO {
	String id = "";
	
	VO(){}
	VO(String id) {
		this.id = id;		
	}
}
public class Simple extends VO
{		
	String str = null;
	Simple() {		
		super(str);	// here you will get compiler error	
	}	
}

you are trying to pass str which is not yet initialized to super constructors.
note: subclass constructor runs *only* successful of super class constructors

[deepu bhadriraju]

Seetharaman Venkatasamy wrote:Let's take this example which is simplified version of your problem

class VO {
	String id = "";
	
	VO(){}
	VO(String id) {
		this.id = id;		
	}
}
public class Simple extends VO
{		
	String str = null;
	Simple() {		
		super(str);	// here you will get compiler error	
	}	
}

you are trying to pass str which is not yet initialized to super constructors.
note: subclass constructor runs *only* successful of super class constructors

Sorry cant get you .can you make necessary changes to my code please

[dennis deems]

deepu bhadriraju wrote:

public class Trainee  extends ConstructChain2{
    int m1,m2,m3;

    public Trainee(int m1, int m2, int m3)
    {
        // your problem is here    
        super(name, dd, mm, yyyy,salary); // to what do name, dd, mm, yyyy, salary refer?
        this.m1 = m1;
        this.m2 = m2;
        this.m3 = m3;
    }
}

[deepu bhadriraju]

Dennis Deems wrote:

deepu bhadriraju wrote:

public class Trainee  extends ConstructChain2{
    int m1,m2,m3;

    public Trainee(int m1, int m2, int m3)
    {
        // your problem is here    
        super(name, dd, mm, yyyy,salary); // to what do name, dd, mm, yyyy, salary refer?
        this.m1 = m1;
        this.m2 = m2;
        this.m3 = m3;
    }
}

Name ,dd,mm,salary refer to variable of grand-parent class..I rectified my mistake.what iam trying to make call the super class constructor without assigning values to it
NOW changed code is
public Trainee(int m1, int m2, int m3,String name,int dd,int mm,int yyyy,int salary)
{
super(name, dd, mm, yyyy,salary);
this.m1 = m1;
this.m2 = m2;
this.m3 = m3;
}