Public, Private, Protected, And Global Keywords in Apex Programming

Public, private, protected, and global can also be referred to as access modifiers. Apex supports these four types of modifiers.

1. public

This keyword is used to Defines a class or method or variable that can be used by any Apex in this application or namespace.

Example

public class Foo {
    public void quiteVisible();
    private void almostInvisible();
}

2. private

This key word is used to Defines a class/method/variable that is only known locally, within the section of code in which it is defined. This is the default scope for all methods and variables that do not have a scope defined.

Example

public class OuterClass {
    private static final Integer MY_INT;
}

3. protected

This keyword defines a method/variable that is visible to any inner classes in the defining Apex class.

Example

public class Foo {
    public void quiteVisible();
    protected void lessVisible();
}

4.global

Defines a class, method, or variable that can be used by any Apex that has access to the class, not just the Apex in the same application.

Example

global class myClass {

	webService static void

	makeContact(String lastName) {
	// do some work

See reference to understand more about apex programming access modifiers.