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Should I Learn Kotlin or Java for Android Development in 2025?

Cowrie
Cowrie
Dev @ Bswen

Purpose

I’m a student who learned Java and enjoys object-oriented programming. I built Android apps in both languages and switched from Java to Kotlin. Now I see Kotlin is the “go-to for Android now” and wonder if I should “go all in Kotlin” or if Java still matters.

The Problem

When I search for Android development advice, I get conflicting information. Some people say Kotlin completely replaced Java. Others say Java is still essential. I want to invest my time wisely but don’t want to learn unnecessary skills.

My Experience

I built my first Android app in Java. It worked fine, but the code felt verbose. Then I tried Kotlin for a second project. The same functionality took less code and felt more natural.

Here’s what I noticed comparing similar features:

MainActivity.java
// Java - Activity creation
public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        Button button = findViewById(R.id.my_button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, "Hello", Toast.LENGTH_SHORT).show();
            }
        });
    }
}
MainActivity.kt
// Kotlin - Activity creation
class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)


        findViewById<Button>(R.id.my_button).setOnClickListener {
            Toast.makeText(this, "Hello", Toast.LENGTH_SHORT).show()
        }
    }
}

The Kotlin version is cleaner. Less boilerplate code, fewer semicolons, and the click listener is more readable.

Null Safety

Null safety is a big difference. In Java, I always need to check for nulls:

// Java - null checks required
String name = getIntent().getStringExtra("name");
if (name != null && !name.isEmpty()) {
    Log.d("MainActivity", "Name: " + name);
}

In Kotlin, null safety is built into the language:

// Kotlin - null safety built-in
val name = intent.getStringExtra("name")
if (!name.isNullOrBlank()) {
    Log.d("MainActivity", "Name: $name")
}

I don’t need to write separate null checks. Kotlin handles this at compile time.

Job Market Reality

I checked job postings for Android development in 2025. Most new postings prefer or require Kotlin. But I still see Java positions for:

  • Maintaining existing Java apps
  • Backend development with Java
  • Enterprise projects with legacy code

So Kotlin is better for new Android projects, but Java still has its place.

What I Think

I think the key questions to ask yourself are:

  1. What type of development do I want to do?
  2. What are the projects I’m interested in?
  3. Do I want to work on new apps or maintain existing systems?

For Android app development specifically, Kotlin gives you modern features and better productivity. For backend or enterprise systems, Java knowledge remains valuable.

Common Mistakes

I made some mistakes when deciding which language to learn:

  • Assuming Kotlin completely replaces Java (they coexist)
  • Focusing too much on syntax differences instead of practical productivity
  • Not considering that different career paths need different languages

Summary

In this post, I shared my experience choosing between Kotlin and Java for Android development. The key point is Kotlin is the strategic choice for new Android projects due to its modern features and Google’s official support, while Java remains essential for legacy systems and backend work.

If you enjoy building Android apps and want to stay current, I recommend learning Kotlin. But don’t discard Java completely—it’s still used in many production systems and will help you understand Android’s history.

Final Words + More Resources

My intention with this article was to help others share my knowledge and experience. If you want to contact me, you can contact by email: Email me

Here are also the most important links from this article along with some further resources that will help you in this scope:

Oh, and if you found these resources useful, don’t forget to support me by starring the repo on GitHub!

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