Learn Apex - 10 Code Examples & CST Typing Practice Test

Apex is a strongly typed, object-oriented programming language developed by Salesforce for building scalable, secure, and automated applications on the Salesforce platform. It allows developers to execute business logic on the server side, integrate external systems, and customize CRM workflows using a syntax similar to Java.

View all 10 Apex code examples →

Apex Counter and Theme Toggle Apex Simple Addition Apex Factorial Apex Fibonacci Sequence Apex Max of Two Numbers Apex Array Sum Apex Even Numbers Filter Apex String Concatenation Apex Counter With Loop Simulation Apex Conditional Increment

Learn APEX with Real Code Examples

Updated Nov 19, 2025

Introduction & Fundamentals Setup & Configuration Architecture & Deep Internals Performance & Security Development Workflow Learning & Career Growth Business & Strategy Examples

Code Sample Descriptions

Apex Counter and Theme Toggle

public class Counter {
    public Integer count = 0;
    public Boolean isDark = false;

    public void updateUI() {
        System.debug('Counter: ' + count);
        System.debug('Theme: ' + (isDark ? 'Dark' : 'Light'));
    }

    public void increment() { count++; updateUI(); }
    public void decrement() { count--; updateUI(); }
    public void reset() { count = 0; updateUI(); }
    public void toggleTheme() { isDark = !isDark; updateUI(); }
}

// Simulate actions
Counter c = new Counter();
c.updateUI();
c.increment();
c.increment();
c.toggleTheme();
c.decrement();
c.reset();

Demonstrates a simple counter with theme toggling using Apex classes and console output (system debug).

Let’s Try →

Apex Simple Addition

public class AddProgram {
    public Integer a = 5;
    public Integer b = 3;
    public Integer sum;

    public void calculate() {
        sum = a + b;
        System.debug('Sum: ' + sum);
    }
}

AddProgram ap = new AddProgram();
ap.calculate();

Adds two numbers and prints the result using System.debug.

Let’s Try →

Apex Factorial

public class FactorialProgram {
    public Integer n = 5;
    public Integer fact = 1;

    public void calculate() {
        for(Integer i = 1; i <= n; i++) {
        fact *= i;
        }
        System.debug('Factorial: ' + fact);
    }
}

FactorialProgram fp = new FactorialProgram();
fp.calculate();

Calculates factorial of a number using a loop.

Let’s Try →

Apex Fibonacci Sequence

public class FibonacciProgram {
    public void generate() {
        List<Integer> fib = new List<Integer>{0,1};
        for(Integer i=2;i<10;i++) {
        fib.add(fib[i-1]+fib[i-2]);
        }
        System.debug('Fibonacci: ' + fib);
    }
}

FibonacciProgram fp = new FibonacciProgram();
fp.generate();

Generates first 10 Fibonacci numbers using Apex lists.

Let’s Try →

Apex Max of Two Numbers

public class MaxProgram {
    public Integer a = 7;
    public Integer b = 10;

    public void findMax() {
        Integer max = (a > b) ? a : b;
        System.debug('Max: ' + max);
    }
}

MaxProgram mp = new MaxProgram();
mp.findMax();

Finds the maximum of two numbers.

Let’s Try →

Apex Array Sum

public class ArraySum {
    public void sumArray() {
        List<Integer> nums = new List<Integer>{1,2,3,4,5};
        Integer sum = 0;
        for(Integer n : nums) { sum += n; }
        System.debug('Sum: ' + sum);
    }
}

ArraySum as = new ArraySum();
as.sumArray();

Sums elements of an integer list.

Let’s Try →

Apex Even Numbers Filter

public class EvenNumbers {
    public void filter() {
        List<Integer> nums = new List<Integer>{1,2,3,4,5,6,7,8,9,10};
        for(Integer n : nums) {
        if(n % 2 == 0) System.debug(n);
        }
    }
}

EvenNumbers en = new EvenNumbers();
en.filter();

Displays even numbers from a list.

Let’s Try →

Apex String Concatenation

public class ConcatStrings {
    public void concat() {
        String str1 = 'HELLO';
        String str2 = 'WORLD';
        String result = str1 + str2;
        System.debug('Concatenated: ' + result);
    }
}

ConcatStrings cs = new ConcatStrings();
cs.concat();

Concatenates two strings and prints the result.

Let’s Try →

Apex Counter With Loop Simulation

public class LoopCounter {
    public void run() {
        Integer count = 1;
        while(count <= 5) {
        System.debug('Counter: ' + count);
        count++;
        }
    }
}

LoopCounter lc = new LoopCounter();
lc.run();

Counts from 1 to 5 using a loop with debug output.

Let’s Try →

Apex Conditional Increment

public class ConditionalIncrement {
    public void run() {
        Integer count = 3;
        if(count < 5) count++;
        System.debug('Counter: ' + count);
    }
}

ConditionalIncrement ci = new ConditionalIncrement();
ci.run();

Increment counter only if below 5.

Let’s Try →

Frequently Asked Questions about Apex

What is Apex?

What are the primary use cases for Apex?

Salesforce triggers & automation. Custom REST & SOAP APIs. Batch & scheduled jobs. Complex CRM business logic. Integrations with external systems. Custom Salesforce Apps & packages

What are the strengths of Apex?

Native integration with Salesforce objects. Secure, scalable execution. Excellent tooling and test framework. Great for enterprise automation. Powerful asynchronous capabilities

What are the limitations of Apex?

Vendor lock-in to Salesforce ecosystem. Strict governor limits. Cannot interact with system file I/O. Restricted multithreading. Must follow Salesforce deployment rules

How can I practice Apex typing speed?

CodeSpeedTest offers 10+ real Apex code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.

Learn Other Programming Languages

C React Python C++Rust TypeScript Kotlin PHP Java C#Ruby Mql Cql N1ql Cypher Gremlin Partiql Haskell Elixir Fsharp View all languages →

Learn Apex - 10 Code Examples & CST Typing Practice Test

Code Sample Descriptions

Apex Counter and Theme Toggle

public class Counter {
    public Integer count = 0;
    public Boolean isDark = false;

    public void updateUI() {
        System.debug('Counter: ' + count);
        System.debug('Theme: ' + (isDark ? 'Dark' : 'Light'));
    }

    public void increment() { count++; updateUI(); }
    public void decrement() { count--; updateUI(); }
    public void reset() { count = 0; updateUI(); }
    public void toggleTheme() { isDark = !isDark; updateUI(); }
}

// Simulate actions
Counter c = new Counter();
c.updateUI();
c.increment();
c.increment();
c.toggleTheme();
c.decrement();
c.reset();

Demonstrates a simple counter with theme toggling using Apex classes and console output (system debug).

Let’s Try →

Apex Simple Addition

public class AddProgram {
    public Integer a = 5;
    public Integer b = 3;
    public Integer sum;

    public void calculate() {
        sum = a + b;
        System.debug('Sum: ' + sum);
    }
}

AddProgram ap = new AddProgram();
ap.calculate();

Adds two numbers and prints the result using System.debug.

Let’s Try →

Apex Factorial

public class FactorialProgram {
    public Integer n = 5;
    public Integer fact = 1;

    public void calculate() {
        for(Integer i = 1; i <= n; i++) {
        fact *= i;
        }
        System.debug('Factorial: ' + fact);
    }
}

FactorialProgram fp = new FactorialProgram();
fp.calculate();

Calculates factorial of a number using a loop.

Let’s Try →

Apex Fibonacci Sequence

public class FibonacciProgram {
    public void generate() {
        List<Integer> fib = new List<Integer>{0,1};
        for(Integer i=2;i<10;i++) {
        fib.add(fib[i-1]+fib[i-2]);
        }
        System.debug('Fibonacci: ' + fib);
    }
}

FibonacciProgram fp = new FibonacciProgram();
fp.generate();

Generates first 10 Fibonacci numbers using Apex lists.

Let’s Try →

Apex Max of Two Numbers

public class MaxProgram {
    public Integer a = 7;
    public Integer b = 10;

    public void findMax() {
        Integer max = (a > b) ? a : b;
        System.debug('Max: ' + max);
    }
}

MaxProgram mp = new MaxProgram();
mp.findMax();

Finds the maximum of two numbers.

Let’s Try →

Apex Array Sum

public class ArraySum {
    public void sumArray() {
        List<Integer> nums = new List<Integer>{1,2,3,4,5};
        Integer sum = 0;
        for(Integer n : nums) { sum += n; }
        System.debug('Sum: ' + sum);
    }
}

ArraySum as = new ArraySum();
as.sumArray();

Sums elements of an integer list.

Let’s Try →

Apex Even Numbers Filter

public class EvenNumbers {
    public void filter() {
        List<Integer> nums = new List<Integer>{1,2,3,4,5,6,7,8,9,10};
        for(Integer n : nums) {
        if(n % 2 == 0) System.debug(n);
        }
    }
}

EvenNumbers en = new EvenNumbers();
en.filter();

Displays even numbers from a list.

Let’s Try →

Apex String Concatenation

public class ConcatStrings {
    public void concat() {
        String str1 = 'HELLO';
        String str2 = 'WORLD';
        String result = str1 + str2;
        System.debug('Concatenated: ' + result);
    }
}

ConcatStrings cs = new ConcatStrings();
cs.concat();

Concatenates two strings and prints the result.

Let’s Try →

Apex Counter With Loop Simulation

public class LoopCounter {
    public void run() {
        Integer count = 1;
        while(count <= 5) {
        System.debug('Counter: ' + count);
        count++;
        }
    }
}

LoopCounter lc = new LoopCounter();
lc.run();

Counts from 1 to 5 using a loop with debug output.

Let’s Try →

Apex Conditional Increment

public class ConditionalIncrement {
    public void run() {
        Integer count = 3;
        if(count < 5) count++;
        System.debug('Counter: ' + count);
    }
}

ConditionalIncrement ci = new ConditionalIncrement();
ci.run();

Increment counter only if below 5.

Let’s Try →

Frequently Asked Questions about Apex

What is Apex?

What are the primary use cases for Apex?

Salesforce triggers & automation. Custom REST & SOAP APIs. Batch & scheduled jobs. Complex CRM business logic. Integrations with external systems. Custom Salesforce Apps & packages

What are the strengths of Apex?

Native integration with Salesforce objects. Secure, scalable execution. Excellent tooling and test framework. Great for enterprise automation. Powerful asynchronous capabilities

What are the limitations of Apex?

Vendor lock-in to Salesforce ecosystem. Strict governor limits. Cannot interact with system file I/O. Restricted multithreading. Must follow Salesforce deployment rules

How can I practice Apex typing speed?

CodeSpeedTest offers 10+ real Apex code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.