This section focuses on writing JEB Python scripts specifically to aid in the analysis of Android applications.

# Dex units

Recall JEB analysis modules produce `IUnit`s, visible in the Project Explorer view:

[![Sample Project, Artifact, Units and sub-units](img/8e2d09f8-small.png)](img/8e2d09f8.png)

## IDexUnit and associated classes

The dex unit interface is your entry-point to access dex elements.

Drop the following file in your JEB scripts/ folder. Open JEB GUI, load a dex or APK file, and execute the script with `F2`.

File: SomeScript.py
```python
from com.pnfsoftware.jeb.client.api import IScript
from com.pnfsoftware.jeb.core.units.code.android import IDexUnit, IApkUnit

class SomeScript(IScript):
  def run(self, ctx):
    prj = ctx.getMainProject()  # current project; None if no project is opened
    dex = prj.findUnit(IDexUnit)  # find the first dex unit
    #dexlist = prj.findUnits(IDexUnit)  # retrieve a list of dex units
    #apk = prj.findUnits(IApkUnit)  # find the first dex unit
    for m in dex.getMethods():
      print m.getSignature()  # print method reference descriptor
```

## dex file representation

The diagram below is a high-level view of JEB types holding dex file information. This structure mirrors the dex file format's. (Not all types are represented, refer to the API reference for a complete list.)

[![](img/72ca0b12-small.png)](img/72ca0b12.png)

# APK units

Android APK are represented by `IApkUnit`s.

File: SomeScript.py
```python
from com.pnfsoftware.jeb.client.api import IScript
from com.pnfsoftware.jeb.core.units.code.android import IApkUnit

class SomeScript(IScript):
  def run(self, ctx):
    prj = ctx.getMainProject()  # current project; None if no project is opened
    apk = prj.findUnits(IApkUnit)  # find the first apk unit
    print(apk.isDebuggable())
    # ...
```

# GUI client's specifics

When a script is run within the GUI client, the `ctx` provided to the `run()` method is `IGraphicalClientContext` (extending `IClientContext`). Additional methods are provided to interact with workspace widgets (unit views, fragments, etc.).

The diagram below shows the connection between UI elements types and the document types they hold.

[![](img/ea260525-small.png)](img/ea260525.png)

Reference type: [IGraphicalClientContext](https://pnfsoftware.com/jeb/apidoc/com/pnfsoftware/jeb/client/api/IGraphicalClientContext.html)

# Decompiler units

The entry-point interface is `IDexDecompilerUnit`, usually a child of an underlying `IDexUnit`. dexdec units produce `IJavaSourceUnit`, holding decompiled elements (classes and methods).

## Accessing the IR

The dex decompiler plugin can load external *Intermediate Representation* (IR) plugins that are called during the decompilation pipeline to further refine and optimize a method decompilation. Those plugins can be compiled as jar, and/or written in Java or Python.

See [this tutorial](https://www.pnfsoftware.com/blog/writing-dexdec-ir-optimizer-plugins/) for a complete step-by-step example on how to write a dexdec IR script plugin, in Python.

[Reference documentation](https://www.pnfsoftware.com/jeb/apidoc/com/pnfsoftware/jeb/core/units/code/android/ir/package-summary.html)

## Accessing the Java AST

Java AST generated by dexdec can be manipulated via the Java AST API.

[Reference documentation](https://www.pnfsoftware.com/jeb/apidoc/com/pnfsoftware/jeb/core/units/code/java/package-summary.html)

[![](img/0fc9300c-small.png)](img/0fc9300c.png)