Access Specifier Error(Cannot find Symbol)

Question

C:\Users\jaina_000\Desktop\learn_java\p1>javac Testp1.java
Testp1.java:6: error: cannot find symbol
                Protection ob = new Protection();
                ^
  symbol:   class Protection
  location: class Testp1
Testp1.java:6: error: cannot find symbol
                Protection ob = new Protection();
                                    ^
  symbol:   class Protection
  location: class Testp1
Testp1.java:7: error: cannot find symbol
                Derived ob1 = new Derived();
                ^
  symbol:   class Derived
  location: class Testp1
Testp1.java:7: error: cannot find symbol
                Derived ob1 = new Derived();
                                  ^
  symbol:   class Derived
  location: class Testp1
Testp1.java:8: error: cannot find symbol
                SamePackage ob2 = new SamePackage();
                ^
  symbol:   class SamePackage
  location: class Testp1
Testp1.java:8: error: cannot find symbol
                SamePackage ob2 = new SamePackage();
                                      ^
  symbol:   class SamePackage
  location: class Testp1
6 errors

package p1;
public class Testp1
    {
    public static void main(String a[])
        {
        Protection ob = new Protection();
        Derived ob1 = new Derived();
        SamePackage ob2 = new SamePackage();
        }
    }

package p1;

public class Protection
    {

    int n = 1;
    private int n_pri = 2;
    protected int n_pro = 3;
    public int n_pub = 4;

    public Protection()
        {
        System.out.println("Inside base constructor.");
        System.out.println(" n = "+n);
        System.out.println("n_pri = "+n_pri);
        System.out.println("n_pro = "+n_pro);
        System.out.println("n_pub = "+n_pub);
        }
    }

package p1;

class Derived extends Protection
    {
    Derived()
        {
        System.out.println("Inside Derived constructor.");
        System.out.println(" n = "+n);
    //  System.out.println("n_pri = "+n_pri);       
        System.out.println("n_pro = "+n_pro);
        System.out.println("n_pub = "+n_pub);
        }
    }

package p1;

class SamePackage{

    SamePackage(){
        Protection p = new Protection();
        System.out.println("Inside SamePackage constructor.");
        System.out.println(" n = "+p.n);                
    //  System.out.println("n_pri = "+p.n_pri);     
        System.out.println("n_pro = "+p.n_pro);
        System.out.println("n_pub = "+p.n_pub);
    }
}

Answer 1

when you have package you can't simply compile or run like you do in classes which doesn't has package .

when you compiled you need to navigate to outside of your package folder and then compile using command javac [package]/[class] .so in your case it should be

javac p1/Testp1.java

and when run use this command java[package.class]..so in your case it should be

java p1.Testp1

make sure you are not inside package [p1] you should outside of package [compile after navigate to folder learn_java through cmd].

finally this is how your cmd looks like

C:\Users\jaina_000\Desktop\learn_java>javac p1/Testp1.java

C:\Users\jaina_000\Desktop\learn_java>java p1.Testp1
Inside base constructor.
 n = 1
n_pri = 2
n_pro = 3
n_pub = 4
Inside base constructor.
 n = 1
n_pri = 2
n_pro = 3
n_pub = 4
Inside Derived constructor.
 n = 1
n_pro = 3
n_pub = 4
Inside base constructor.
 n = 1
n_pri = 2
n_pro = 3
n_pub = 4
Inside SamePackage constructor.
 n = 1
n_pro = 3
n_pub = 4
C:\Users\jaina_000\Desktop\learn_java>