Java Virtual Machine

This repo has a java virtual machine program, taking in a .class file and running the program as a JVM would. This JVM is written in Python and can run java programs that include basic arithmetic and printing of strings.

Installing

To get a development env running install: codecov, numpy, coverage, bitstring, unittest, and binascii.

$ pip install numpy
Collecting numpy
Downloading https://files.pythonhosted.org/packages/4e/9d/c129d78e6b942303b762ccfdf1f8339de80c5e6021b14ef0c99ec5bdc6aa/numpy-1.16.3-cp37-cp37m-win_amd64.whl (11.9MB)
100% |████████████████████████████████| 11.9MB 865kB/s
Installing collected packages: numpy
Successfully installed numpy-1.16.3

and repeat until finished.

To download (right click and save as) pip download get-pip.py file https://bootstrap.pypa.io making sure to save as a .py file. Navigate to the folder containing the file and run the command:

$ python get-pip.py
Collecting pip
Using cached https://files.pythonhosted.org/packages/f9/fb/863012b13912709c13cf5cfdbfb304fa6c727659d6290438e1a88df9d848/pip-19.1-py2.py3-none-any.whl
Collecting wheel
Downloading https://files.pythonhosted.org/packages/96/ba/a4702cbb6a3a485239fbe9525443446203f00771af9ac000fa3ef2788201/wheel-0.33.1-py2.py3-none-any.whl
Installing collected packages: pip, wheel
Successfully uninstalled pip-19.1
Successfully installed pip-19.1 wheel-0.33.1

Getting Started

To run the JVPM use command below, HelloWorld can be replaced with any class file name. The file must be in the javafiles folder in jvpm; ".class" post-fix is added by the program.

$ python3 jvpm/main.py HelloWorld
HelloWorld!

To create a .class file from a .java file, navigate to the directory containing the java file. Run the command below:

$ javac HelloWorld.java

In order to run the javac command you must add the jdk bin filder to PATH, read: https://stackoverflow.com/questions/1678520/javac-not-working-in-windows-command-prompt

Running unittests

To run unittest, use command below.

$ python3 -m unittest
......
----------------------------------------------------------------------
Ran 48 tests in 0.329s

OK

We use test code coverage tools to make sure we are covering as much of the program as possible with the tests. To generate the test code coverage, do

$ coverage run -m unittest

To view the results, do

$ coverage report
Name                                                 Stmts   Miss  Cover
------------------------------------------------------------------------
jvpm\__init__.py                                         0      0   100%
jvpm\packages\CPInfo.py                                 82     16    80%
jvpm\packages\__init__.py                                1      0   100%
jvpm\packages\access_flag_translater_dictionary.py       4      0   100%
jvpm\packages\jvpm_dict.py                               7      0   100%
jvpm\packages\jvpm_methods.py                          144     18    88%
jvpm\packages\jvpm_opcodes.py                          147     15    90%
jvpm\packages\pool_methods.py                           40      0   100%
jvpm\packages\pool_translate.py                        167     12    93%
jvpm\packages\read_attribute.py                        125     13    90%
jvpm\packages\stack.py                                  13      0   100%
test\__init__.py                                         0      0   100%
test\test_jvpm.py                                      685      3    99%
------------------------------------------------------------------------
TOTAL                                                 1415     77    95%

Contributors

• drsjb80
• LSmith-Zenoscave
• zkhalido
• Cjohnson187
• G-Leib
• DominickNola
• minouye2
• Azuesflip
• elopezh1

All contributors can be found on GitHub.