Getter and setter methods in Java - Step-by-Step Execution

Concept Flow - Getter and setter methods

Create private variable

↓

Define getter method

↓

Define setter method

↓

Use getter to read value

↓

Use setter to change value

↓

Value updated safely

↓

END

This flow shows how a private variable is accessed and changed safely using getter and setter methods.

Execution Sample

Java

class Person {
  private String name;
  public String getName() { return name; }
  public void setName(String newName) { name = newName; }
}

Person p = new Person();
p.setName("Alice");
System.out.println(p.getName());

This code creates a Person object, sets the name to "Alice" using the setter, then prints the name using the getter.

Execution Table

Step	Action	Variable 'name' Value	Output
1	Create Person object	null
2	Call setName("Alice")	"Alice"
3	Call getName()	"Alice"	Alice
4	End of program	"Alice"

💡 Program ends after printing the name 'Alice' retrieved by the getter.

Variable Tracker

Variable	Start	After setName("Alice")	Final
name	null	"Alice"	"Alice"

Key Moments - 2 Insights

Why can't we access the variable 'name' directly?

Because 'name' is private, it can only be accessed inside the class. We use getter and setter methods to read and change it safely, as shown in steps 2 and 3 of the execution table.

What happens if we call getName() before setName()?

The variable 'name' would be null because it has not been set yet. This is shown in step 1 where 'name' starts as null.

Visual Quiz - 3 Questions

Look at the execution table, what is the value of 'name' after step 2?

A null

B "Alice"

C "Bob"

D Empty string

💡 Hint

Check the 'Variable 'name' Value' column at step 2 in the execution table.

At which step does the program print output?

A Step 3

B Step 1

C Step 2

D Step 4

💡 Hint

Look at the 'Output' column in the execution table to find when 'Alice' is printed.

If we remove the setter method, what will happen when we try to set the name?

A The name will be set anyway.

B The name will be set to null.

C Compilation error because setName() does not exist.

D The getter will return an empty string.

💡 Hint

Think about what happens if you call a method that is not defined in the class.

Concept Snapshot

Getter and setter methods allow controlled access to private variables.
Syntax:
private Type var;
public Type getVar() { return var; }
public void setVar(Type val) { var = val; }
Use getters to read and setters to update values safely.

Full Transcript

This visual execution shows how getter and setter methods work in Java. First, a private variable 'name' is created inside the Person class. We cannot access 'name' directly from outside because it is private. Instead, we define a getter method getName() to read the value and a setter method setName() to change it. When we create a Person object, 'name' starts as null. Calling setName("Alice") changes 'name' to "Alice". Then calling getName() returns "Alice", which is printed. This approach protects the variable and allows safe access and modification. The execution table tracks each step and variable value. Key moments clarify why direct access is not allowed and what happens if we get before setting. The quiz tests understanding of variable values and method roles. The snapshot summarizes the syntax and purpose of getters and setters.