JAVA: how to show the output in other class using getter/setter

Question

1.00/5 (1 vote)

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Based on the question, i want to have the output is shown based on the second method used using getter. but the error shown : null pointer.

Note: i already try it by using the "Static" in variable.

So, is there any other way to calling the getter without use "static" ?

means, in this below method part :

Java

public void secondMethod_getTheName(){
System.out.println("Name: "+theModel.getName());}

What I have tried:

model class

Java

package com.SetterAndGetter;

public class model {

	private  int id;
	private  String name;
	private  int Age;

	public  int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public  String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public  int getAge() {
		return Age;
	}

	public void setAge(int age) {
		Age = age;
	}

	@Override
	public String toString() {
		return "model [id=" + id + ", name=" + name + ", Age=" + Age + "]";
	}

}

myMethod Class

Java

package com.SetterAndGetter;

public class myMethod {

	public model theModel;

	public void setTheName() {
		String name = "mike";

		theModel = new model();
		theModel.setName(name);
	}

	public void getTheName() {

		System.out.println("The name is: " + theModel.getName());
	}

}

Main Class

Java

package com.SetterAndGetter;


public class mainApp {
	private model theModel;


	public void secondMethod_getTheName() {

		System.out.println("Name: "+theModel.getName());


	}

	public static void main(String[] args) {

		myMethod obj1 = new myMethod();
		obj1.setTheName();
		obj1.getTheName();

		mainApp obj2 = new mainApp();
		obj2.secondMethod_getTheName();

	}
}

Posted 26-Mar-18 21:40pm

Asyraf Patt

Updated 27-Mar-18 21:21pm

Add a Solution

2 solutions

Solution 1

Quote:
System.out.println("Name: "+theModel.getName());

You are using an object without having instantiated it. You have to create the object (and set its name), e.g.

Java

mainApp obj2 = new mainApp();
obj2.theModel = new model();
obj2.theModel.setName("foo");
obj2.secondMethod_getTheName();

Posted 26-Mar-18 22:09pm

CPallini

Comments

Asyraf Patt 27-Mar-18 4:45am

public void secondMethod_getTheName() {

System.out.println("Name: "+theModel.getName());
}

How should i print mike, by using the same getter ?

CPallini 27-Mar-18 6:15am

You cannot. You have to create an instance of myMethod (as you have already done) in order to get it (alternatively you could replace "foo", with "mike" in my code).
Your model class is almost fine (it lacks a proper ctor, in my opinion) but it looks you don't master how to access it.

Maciej Los 27-Mar-18 6:45am

5ed!

CPallini 27-Mar-18 11:30am

Thank you very much.

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Asyraf Patt · Accepted Answer · 2018-03-27T21:22:00

First Solution

Mymethod class

package com.SetterAndGetter;

public class myMethod {

	public model theModel;

	public static  String theName;

	public void setTheName(String tempName) {
		theName = "john";
		tempName = theName;


		theModel = new model();
		theModel.setName(theName);
	}

	public void getTheName() {

		System.out.println("The name is: " + theModel.getName());

	}

}

Model Class

package com.SetterAndGetter;

public class model {

	private int id;
	private  String name;
	private  int Age;



	public  int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public  String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public  int getAge() {
		return Age;
	}

	public void setAge(int age) {
		Age = age;
	}

	@Override
	public String toString() {
		return "model [id=" + id + ", name=" + name + ", Age=" + Age + "]";
	}

}

Main Method

package com.SetterAndGetter;

public class mainApp {
	private myMethod mm;

	public void secondMethod_getTheName() {

		System.out.println("the second method: "+myMethod.theName);

	}

	public static void main(String[] args) {

		myMethod obj1 = new myMethod();
		obj1.setTheName(null);
		obj1.getTheName();

		mainApp obj2 = new mainApp();
		obj2.secondMethod_getTheName();


	}
}

Second Solution
by using the inheritance

my method class

package com.SetterAndGetter;

public class myMethod {

	/**
	 * Create new object of the model Class
	 */
	public static model Model = new model();

	private String tempName;

	public myMethod() {
	}

	public myMethod(String stempName) {

		// reference the variable as tempName == stempName
		this.tempName = stempName;

		//define value of stempName as mike
		stempName = "mike";

		//Set the name
		Model.setName(stempName);


	}

	public void dispMethod(){

		System.out.println("Use Getter: "+Model.getName());
	}

}

second method class

package com.SetterAndGetter;

/**
 * Created by Asyraf-PC on 3/28/2018.
 */

public class mySecondMethod extends myMethod {


    public void secondMethodDisplay() {

        System.out.println("Use Second Getter: "+Model.getName());

    }
}

model

package com.SetterAndGetter;

public class model {

	private int id;
	private  String name;
	private  int Age;



	public  int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public  String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public  int getAge() {
		return Age;
	}

	public void setAge(int age) {
		Age = age;
	}

	@Override
	public String toString() {
		return "model [id=" + id + ", name=" + name + ", Age=" + Age + "]";
	}

}

main App

package com.SetterAndGetter;

public class mainApp {


	public static void main(String[] args) {

	myMethod obj = new myMethod("");
	obj.dispMethod();

	mySecondMethod obj2 = new mySecondMethod();
	obj2.secondMethodDisplay();


	}
}