//父类
public abstract class fathr {
    private final String kind;
    public fathr(String k) {
        this.kind = k;    
    }
}

//子类
public class son extends fathr{
        int a,b;

    public son() {
        super("test");
    }
    
    public son(int a,int b)
    {
        this.a = a;
        this.b = b;        
    }
}

public son() {
    super("test");
}

public son(int a,int b)
{
    this(); //这样也是可以的，所以和super，this应该没关系，看反编译具体如何实现
    this.a = a;
    this.b = b;        
}