Three simple steps
How to use this tool?
This free online converter translates Kotlin source code into Java in three simple steps.
- Step 1
Add your Kotlin code
Type, paste, or upload the Kotlin code you want to translate.
- Step 2
Convert the code
Click Convert to translate the source code into Java.
- Step 3
Review the result
Review, copy, or download the resulting Java code from the output editor.
See it in action
Examples of Kotlin to Java conversion
These examples show Kotlin source code and the corresponding Java translation. Generated results can vary as AI models are updated.
Example 1
Is String Palindrome
Program that checks if a string is a palindrome or not.
Kotlin code
Java code
Example 2
Even or Odd
A well commented function to check if a number if odd or even.
Kotlin code
Java code
Language comparison
Key differences between Kotlin and Java
| Characteristic | Kotlin | Java |
|---|---|---|
| Syntax | Kotlin has a more concise and expressive syntax compared to Java. It supports features like null safety, extension functions, and operator overloading. | Java has a more verbose syntax compared to Kotlin. It does not support null safety, extension functions, or operator overloading. |
| Paradigm | Kotlin is a multi-paradigm language that supports both object-oriented and functional programming. | Java is an object-oriented language that supports some functional programming concepts through the use of lambda expressions. |
| Typing | Kotlin is a statically typed language that supports type inference. | Java is a statically typed language that does not support type inference. |
| Performance | Kotlin has similar performance to Java as it compiles to bytecode that runs on the Java Virtual Machine (JVM). | Java has good performance due to its efficient bytecode and just-in-time (JIT) compilation. |
| Libraries and frameworks | Kotlin has good interoperability with Java libraries and frameworks. It also has its own set of libraries and frameworks like Ktor and kotlinx. | Java has a vast ecosystem of libraries and frameworks like Spring, Hibernate, and Apache Struts. |
| Community and support | Kotlin has a growing community and is backed by JetBrains, the company behind popular IDEs like IntelliJ IDEA and Android Studio. | Java has a large and mature community with extensive documentation and support. |
| Learning curve | Kotlin has a relatively low learning curve for Java developers as it is interoperable with Java and has a similar syntax. It also has good documentation and resources. | Java has a moderate learning curve for beginners due to its verbose syntax and concepts like object-oriented programming and memory management. |
Common questions
Frequently Asked Questions
How do I convert Kotlin to Java?
Paste your Kotlin code into the input box, confirm the languages are set to Kotlin and Java, and click Convert. CodeConvert AI analyzes your Kotlin code and generates equivalent Java code in seconds, preserving the original logic and structure.
What are the main differences between Kotlin and Java?
Kotlin and Java differ in syntax, type system, standard libraries, and common idioms, so copying code line for line usually will not compile. The converter maps each Kotlin construct to its closest Java equivalent. See the comparison table below for the key differences between Kotlin and Java.
Is the converted Java code accurate?
The AI produces high-quality Java code that preserves the behavior of your original Kotlin code and follows Java conventions. It handles common patterns, data structures, and idioms for both Kotlin and Java. For large or performance-critical code, review and test the Java output before using it in production.
Can I convert an entire Kotlin project to Java?
You can convert Kotlin files one at a time by pasting each file's code. For a full migration, convert each file and then review how classes, dependencies, and project structure map from Kotlin to Java. Signing in for free raises the input limit to 25,000 characters per conversion for larger files.
Can I convert Java back to Kotlin?
Yes. CodeConvert AI converts in both directions, so you can convert Java to Kotlin just as easily using our Java to Kotlin converter. Try the Java to Kotlin Converter
Is the Kotlin to Java converter free, and do I need to install anything?
Yes, it is free and runs in your browser with nothing to install and no IDE extension required. You can convert Kotlin to Java without an account for up to 5 conversions per day. Sign in for free for higher limits.
What are the benefits of signing in?
Signing in unlocks CodeConvert AI's Pro converter with more powerful AI models, a built-in chat assistant, code execution, saved conversion history, and personal notes. Every free account includes 5 credits and supports up to 25,000 characters of input per conversion, with no credit card required.
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