Jython

Jython
Jython Logo
FamilyJVM-hosted
First appearedJanuary 17, 2001; 25 years ago (2001-01-17)
Stable release
2.7.4 Edit this on Wikidata / 18 August 2024; 2 years ago (18 August 2024)
Implementation languagePython, Java
PlatformJava virtual machine
OScross-platform
LicensePython Software Foundation (for older releases see License terms)
Websitewww.jython.org Edit this at Wikidata

Jython, named JPython until 1999, is an implementation of the programming language Python designed to run on the Java virtual machine of the Java platform. It is free and open-source software released with a Python Software Foundation License.

Overview

Jython programs can import and use any Java class. Except for some standard modules, Jython programs use Java classes instead of Python module. Jython includes almost all of the modules in a standard Python language distribution, lacking only some of the modules implemented originally in C, and can call Java classes, such as the Java Class Library. For example, a user interface in Jython could be written with Swing, Abstract Window Toolkit (AWT), or Standard Widget Toolkit (SWT). Jython compiles Python source code to Java bytecode (an intermediate representation) either on demand or statically.

from java.io import FileWriter
from java.lang import System
from java.util import Date

# Write out the current date and the system info
message = "Run on " + str(Date()) + " by Java " + System.getProperty("java.version")
FileWriter("sys_info.txt").append(message).close()

print message

Because Jython maps threads directly onto Java threads, it avoids the global interpreter lock which standard Python uses.

Jython cannot make use of Java's type system or generics. Jython uses the primitive wrapper classes primarily for unboxing Java API return types back to Jython internal types.

Jython internal type Coerced Java type
org.python.core.PyNone null
org.python.core.PyObject java.lang.Object
org.python.core.PyInteger int, java.lang.Integer
org.python.core.PyFloat double, java.lang.Double
org.python.core.PyUnicode java.lang.String
org.python.core.PyList java.lang.List
org.python.core.PyDictionary java.lang.Map

History

Jython was initially created in late 1997 to replace C with Java for performance-intensive code accessed by Python programs. It moved to SourceForge in October 2000. The Python Software Foundation awarded a grant in January 2005. Jython 2.5 was released in June 2009.

Status and roadmap

The most recent release is Jython 2.7.4. It was released on August 18, 2024 and is compatible with Python 2.7.

Python 3 compatible changes are planned in Jython 3 Roadmap.

Although Jython implements the Python language specification, it has some differences and incompatibilities with CPython, which is the reference implementation of Python.

License terms

From version 2.2 on, Jython (including the standard library) is released under the Python Software Foundation License (v2). Older versions are covered by the Jython 2.0, 2.1 license and the JPython 1.1.x Software License.

The command line interface interpreter is available under an Apache software license.

Use

See also

References

  1. ↑ Wierzbicki, Frank (March 22, 2015). "jython: 3d8067c56a1d News". Retrieved March 28, 2015.
  2. ↑ "Release 2.7.4". August 18, 2024. Retrieved August 22, 2024.
  3. ↑ "JythonFaq/GeneralInfo - JythonWiki". April 3, 2014. Retrieved March 28, 2015.
  4. ↑ Jython. "Package org.python.core". javadoc.io. Jython. Retrieved July 15, 2026.
  5. ↑ Wierzbicki, Frank (June 16, 2009). "Jython 2.5.0 Final is out!". Retrieved July 2, 2009.
  6. ↑ "News". Jython. Retrieved April 19, 2020.
  7. ↑ "Jython 3 Roadmap". Jython. Retrieved October 14, 2022.
  8. ↑ "JythonFaq". Jython's project. Retrieved July 5, 2009.
  9. ↑ "Differences between CPython and Jython". Jython's project. Archived from the original on October 7, 2023. Retrieved July 5, 2009.
  10. ↑ "The Jython License". Jython's project. Archived from the original on October 9, 2018. Retrieved February 9, 2008.
  11. ↑ "Introducing Ignition - Ignition User Manual 7.9 - Ignition Documentation". docs.inductiveautomation.com. Retrieved April 24, 2019.