Joining method from another class in java -

i'm trying understand java trying several things out. i'm using 2 classes in same package. 1 called box, other 1 called testbox. want calculate area of company box using calculatearea(). function in class testbox. function calculatearea in box not respond function in testbox. i'm missing link between these 2 classes. seems simple problem, have not found solution yet. can please me out?

package box;  public class box {      int length;     int width;      public static void main(string[] args) {         box company = new box();          company.length = 3;         company.width = 4;         int area = company.calculatearea();     } } 

package box;  public class testbox {      int length;     int width;      int calculatearea(){         int area = length * width;         system.out.println("area= " + area);     return area;     } } 

i think have clarify bit design, mean classes box , testbox should do, advice use use ide such eclipse or intellij idea helping syntax highlight , founding possible errors.

what dealing encapsulation,

packing of data , functions single component.

so feasible area of box calculated box class itself.

about code, possible solution be:

package com.foo;  public class main {      public static void main(string[] args) {         box box = new box(3, 4);          int area = box.calculatearea();          system.out.println("box area is: " + area);     } }  class box {      private int l;     private int w;      box(int length, int width) {         l = length;         w = width;     }      int calculatearea() {         return l * w;     } } 

another possible approach be

package com.foo;  public class main {       public static void main(string[] args) {         box box = new box(3, 4);          testbox testbox = new testbox();          int area = testbox.calculatearea(box);          system.out.println("box area is: " + area);     } }  class box {      private int l;     private int w;      box(int length, int width) {         l = length;         w = width;     }      public int getlength() {         return l;     }      public int getwidth() {         return w;     }  }  class testbox {     int calculatearea(box box) {         return box.getlength() * box.getwidth();     } 

if want have separate class doing job, not like, function computing area related box , works on box variables, prefer first one, should better have more details in case.

i hope helps.