从不同的 package JAVA 调用方法

Question

I have two packages; pack1 and pack2. in pack1 I have two classes the main called Prog and another one called ClassA. In pack2 I have one class called ClassB.

I am trying to understand why I can't call a method from ClassB using the object. I can do that using the main class but not with another class.

Here's the code:

package pack1;
import pack2.ClassB;

public class Prog {
    public static void main(String[] args){

    }
}

Code for ClassA

package pack1;
import pack2.ClassB;

public class ClassA {
    ClassB o3 = new ClassB();
    // Error won't compile
    System.out.println(o3.getText());

}

Code for ClassB:

package pack2;

public class ClassB {
    final String TEXT = "This is a text";

    public String getText(){
        return TEXT;
    }
}

Answer 1

The problem here isn't that you can't access the method. The problem is that statements must be enclosed either in a constructor, amethod-declaration or an initializer-block. So this would be valid code for example:

enter codepackage pack1;
import pack2.ClassB;

public class ClassA {
    ClassB o3 = new ClassB();

    public void someMethod(){
        System.out.println(o3.getText());
    }
}

Answer 2

//pack1 code here

package pack1;

import pack2.ClassB;

class ClassA {

}

public class Prog {

public static void main(String[] args) {
// write your code here
    ClassB o3 = new ClassB();
    // Error won't compile
    System.out.println(o3.getText());


}

}

//pack2 code here

package pack2;

public class ClassB { final String TEXT = "This is a text";

public String getText() {
    return TEXT;
}

}[You don't need to create classA you can directly import pack2 and its class,method]