Jython and Python are two versions of the same language, used for different contexts. Jython is a Java implementation of Python, which, in a nutshell, means it's Python running on a Java Virtual Machine (JVM) environment. It writes like Python, but it can access the full potential of Java libraries.

We'll be looking at the differences between Jython and Python and why Jython is becoming increasingly popular among Java and Python developers, who are learning how to use this implementation in the context of JVMs to improve productivity and achieve faster results.

Rather than debating which one is better, since they share the same core features, we'll be showing how connecting Python to Java through Jython opens up a whole new world of possibilities.

Table of Contents

  1. What is Python?
  2. What is Java?
  3. What is Jython?
  4. Jython vs. Python: Differences
  5. Jython vs. Python: Benefits
  6. Python+Java=Jython

What is Python?

"Python" refers to the original C-based programming language, so whenever you read Python, it means CPython. It got so popular that the C became implied, being Python the common designation and the reference all the different implementations compare to.

Python is one of the most popular object-oriented programming languages around, often compared with Perl, Ruby, and Java. Python is widely appreciated because of its syntax simplicity and readability, faster development, and powerful applications.

Most Popular Programming Languages in 2020
Source: GitHub Octoverse

Python's main features are:

Syntax - Python is easy to write, read and understand, making it ideal to build prototypes and accelerate the development process. Its clarity and conciseness make it an ideal language for beginners.

Applications - It may be suited to start in programming, but Python has an advanced application potential. Python is widely used in data science, machine learning, data visualization, and data processing.

Libraries - The power of Python lies in the libraries available that cover the most common programming tasks such as connecting to web servers, reading and modifying files, searching text with regular expressions, and some more advanced endeavors like machine learning.

Easily extendable - developers can expand the capabilities of Python by adding new modules compiled in C, by embedding it into applications, or by grouping the code itself into modules and packages for re-use.

Compatibility - Python runs in all OSs: Mac OS X, Windows, Linux, and Unix. Android and iOS also make the list thanks to unofficial builds.

Free - like the best things in life, Python doesn't cost anything. Anyone can download and use Python in their applications. And since it's available under an open-source license, it can also be freely modified and re-distributed.

What is Java?

Java is also a popular object-oriented programming language, with a similar syntax to C++ and C. It is statically typed, which means it performs type checking at compile-time, contrasting with Python's dynamically-typed programming language characteristics.

The core features of Java are:

Syntax - Java's syntax looks a bit cumbersome compared to Python, using more code and with stricter rules. The presence of brackets makes it even less attractive and more prone to validation mistakes.

Applications - Java is used everywhere, from web applications to desktop GUI apps, enterprise applications, and integrated systems.

Libraries - There is a vast number of Java libraries available that can be used for almost anything.

Extensions - Java's core capabilities can be extended through a set of packages or classes bundled in a JAR file.

Compatibility - Java runs in Java Virtual Machine environments, which can run in any device or operating system following the "Write once, run anywhere" principle.

Free - It is free and available for general-purpose computing.

To know more about how Python differs from Java, we recommend reading our in-depth comparison.

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What is Jython?

Now that we have an idea of what Python and Java are, it will be easier to grasp the concept of Jython. As we said initially, Jython is a Java implementation of Python, developed to run in Java platforms and use Java classes. The name itself is a tell: Jython=Java+Python.

It has most of the characteristics we described above for Python, opening up new possibilities to programmers that can use Python's syntax and logic in a Java Virtual Machine (JVM) environment, with the bonus of using Java's libraries.

Jython’s main features are:

Elegant syntax - It shares the same syntax as Python and all its simplicity, clarity, and conciseness.

Applications - The main application of Jython is the integration of Java with Python, enabling developers to use the JVM library while writing in Python semantics within a Java platform. Java is a great resource for Machine Learning since it's easy to debug while handling large-scale operations.

Libraries - Jython can use all Java libraries. It's the most appealing part for Python developers since they can access Java libraries like Weka or Deeplearning4j.

Compatibility - Jython runs in any Java Virtual Machine, and JVM runs in most devices, so Jython runs, basically, anywhere.

Free - Jython is available for commercial and non-commercial use.

Jython is the bridge connecting the worlds of Java and Python, allowing for seamless interaction between these two languages.

Differences between Python and Jython

Python and Jython share many of the same core attributes. But Jython does what Python can do with the added possibilities of Java, enabling the use of a Pythonesque syntax to write Jython modules that can tap into the vast amount of Java libraries for application integration.

Jython Python


Cross-platform (requires JVM)


File Extension




Web applications; Desktop GUI Apps; enterprise solutions; embedded systems.

Scientific and numeric computing; Machine Learning applications; image processing; language development.


Written in Java 

Written in C

Benefits of Jython

Now that we've established what Jython is, what it is not, and what it is good for, let's find out why it is such an attractive option for developers everywhere. Jython not only bridges the gap between the possibilities offered by Python and Java but also creates new ones.

It's an easy programming language to learn and implement that has a lot of power thanks to the huge amount of Java libraries it brings. It can be used to create quick Graphical User Interfaces, call to a database, create frames or test the code quickly for errors.

Visually, it even looks better. Like Python, Jython relies on indentations and spacing instead of brackets to divide code blocks and define structure, limiting the presence of unnecessary symbols in the code.

Let’s compare a simple if-statement in Java against the same in Python/Jython:

Java if-statement

x = 100;
if (x > 0) {
    System.out.println("Variable value is greater than zero");
} else {
    System.out.println("Variable value is less than zero");

Python/Jython if-statement

x = 100
if x > 0:
    print 'Variable value is greater than zero'
    print 'Variable value is less than zero'

The latter version looks cleaner, leaner, and more concise. No curly braces, no single inverted commas, and no brackets. The similarities with Python's syntax make Jython a valuable tool to help programmers code Java applications without the complexities and demands of coding in Java.

Access to Java's libraries is another major benefit since there are libraries for almost anything. Programmers can work faster, saving time in the development and testing stages.

Jython also works wherever JVM works. The Python code used in a Jython application is compiled as Java bytecode, an instruction set written for the Java Virtual Machine. Since JVM is designed to work anywhere, this feature promotes cross-platform portability and improves performance.


So, it is not a Python vs. Jython situation, but a winning association of features that makes Jython a powerful mix of Python and Java. Jython combines the lightness and versatility of Python with the potential of the Java universe, making it a serious option for developers looking to dip their toes in High-Level Language waters using a simpler syntax.

Either for Java or Python developers, Jython might be worth looking at to expand programming capabilities and create powerful applications with an elegant syntax.

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