static, final, this, super keywords in apex

Important keywords in Apex Programming

Below are some of the important keywords in Apex programming language.

static

This keyword defines a method/variable that is only initialized once and is associated with an (outer) class, and initialization code. We can call static variables/methods by class name directly. No need of creating an instance of a class.

Example

public class OuterClass {

	// Associated with instance
	public static final Integer MY_INT;
	
	// Initialization code
	static {
	MY_INT = 10;
	}
	
}

final

This keyword is used to Defines constants and methods that can’t be overridden.

Example

public class myCls {
    static final Integer INT_CONST;
}

this

This keyword represents the current instance of a class, in constructor chaining.

Example

public class Foo {
	
	public Foo(String s) {/* … */}
	
	public foo() {
	
	this('memes repeat'); }
	
}

super

This keyword invokes a constructor on a superclass.

Example

public class AnotherChildClass extends InnerClass {
	AnotherChildClass(String s) {
		super();
		// different constructor, no args
	}
}

return

This keyword returns a value from a method.

Example

public Integer sum() {
    return int_var;
}

transient

This keyword declares instance variables that cannot be saved, and should not be transmitted as part of the view state, in Visualforce controllers and extensions.

Example

transient integer currentValue;

null

This keyword defines a null constant that can be assigned to any variable.

Example

Boolean b = null;

Like other programming languages, there are many other keywords in Apex programming language. We will see those in other posts.