java, get set methods

113,168

To understand get and set, it's all related to how variables are passed between different classes.

The get method is used to obtain or retrieve a particular variable value from a class.

A set value is used to store the variables.

The whole point of the get and set is to retrieve and store the data values accordingly.

What I did in this old project was I had a User class with my get and set methods that I used in my Server class.

The User class's get set methods:

public int getuserID()
    {
        //getting the userID variable instance
        return userID;
    }
    public String getfirstName()
    {
        //getting the firstName variable instance
        return firstName;
    }
    public String getlastName()
    {
        //getting the lastName variable instance
        return lastName;
    }
    public int getage()
    {
        //getting the age variable instance
        return age;
    }

    public void setuserID(int userID)
    {
        //setting the userID variable value
        this.userID = userID;
    }
    public void setfirstName(String firstName)
    {
        //setting the firstName variable text
        this.firstName = firstName;
    }
    public void setlastName(String lastName)
    {
        //setting the lastName variable text
        this.lastName = lastName;
    }
    public void setage(int age)
    {
        //setting the age variable value
        this.age = age;
    }
}

Then this was implemented in the run() method in my Server class as follows:

//creates user object
                User use = new User(userID, firstName, lastName, age);
                //Mutator methods to set user objects
                use.setuserID(userID);
                use.setlastName(lastName);
                use.setfirstName(firstName);               
                use.setage(age); 
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113,168
Jonatan Jonsson
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Jonatan Jonsson

Updated on February 18, 2020

Comments

  • Jonatan Jonsson
    Jonatan Jonsson over 4 years

    This question has been asked before, but even after reading:

    Java "Get" and "Set" Methods

    Java Get/Set method returns null

    And more I still don't understand how to solve my problem.

    When accessing variables in a class using get methods from another class I receive the value null.

    How do I recieve my correct values instead of null?


    This is the class where I try to get my variables FROM (not everything included).

    public class RLS_character_panel extends javax.swing.JPanel implements ActionListener, ItemListener { 
    
        private String name1 = "hello"; 
    
        public String getName1() { 
            return name1; 
        } 
    
        public void setName1(String name1) { 
            this.name1 = name1; 
        } 
    
    } 
    

    This is the class where i try to get the values TO. This class extends JFrame so that I can add a JPanel which displays the variable. (the JPanel is yet another class called: RLS_strid_panel , which is added upon this frame).

    public class RLS_strid_java extends JFrame { 
    
        RLS_character_panel test = new RLS_character_panel(); 
    
        String name1 = test.getName1(); 
    
        RLS_strid_panel p = new RLS_strid_panel(namn1); 
    
        // constructor
        public RLS_strid_java(String titel) { 
            super(titel); 
            this.setSize(1000, 772); 
            this.setVisible(true); 
            this.setResizable(false); 
            this.add(p); 
        } 
    }
    

    the Jpanel Displays null.