How to call a method in another class in Java?

Currently I have two classes. a classroom class and a School class. I would like to write a method in the School class to call public void setTeacherName(String newTeacherName) from the classroom class.

classroom.java

public class classroom { private String classRoomName; private String teacherName; public void setClassRoomName(String newClassRoomName) { classRoomName = newClassRoomName; } public String returnClassRoomName() { return classRoomName; } public void setTeacherName(String newTeacherName) { teacherName = newTeacherName; } public String returnTeacherName() { return teacherName; } } 

School.java

import java.util.ArrayList; public class School { private ArrayList<classroom> classrooms; private String classRoomName; private String teacherName; public School() { classrooms = new ArrayList<classroom>(); } public void addClassRoom(classroom newClassRoom, String theClassRoomName) { classrooms.add(newClassRoom); classRoomName = theClassRoomName; } // how to write a method to add a teacher to the classroom by using the // classroom parameter // and the teachers name } 

5 Answers

You should capitalize names of your classes. After doing that do this in your school class,

Classroom cls = new Classroom(); cls.setTeacherName(newTeacherName); 

Also I'd recommend you use some kind of IDE such as eclipse, which can help you with your code for instance generate getters and setters for you. Ex: right click Source -> Generate getters and setters

Try this :

public void addTeacherToClassRoom(classroom myClassRoom, String TeacherName) { myClassRoom.setTeacherName(TeacherName); } 

class A{ public void methodA(){ new B().methodB(); //or B.methodB1(); } } class B{ //instance method public void methodB(){ } //static method public static void methodB1(){ } } 

in School,

public void addTeacherName(classroom classroom, String teacherName) { classroom.setTeacherName(teacherName); } 

BTW, use Pascal Case for class names. Also, I would suggest a Map<String, classroom> to map a classroom name to a classroom.

Then, if you use my suggestion, this would work

public void addTeacherName(String className, String teacherName) { classrooms.get(className).setTeacherName(teacherName); } 

Instead of using this in your current class setClassRoomName("aClassName"); you have to use classroom.setClassRoomName("aClassName");

You have to add the class' and at a point like

yourClassNameWhereTheMethodIs.theMethodsName(); 

I know it's a really late answer but if someone starts learning Java and randomly sees this post he knows what to do.