{"id":521,"date":"2016-10-09T08:18:47","date_gmt":"2016-10-09T16:18:47","guid":{"rendered":"https:\/\/www.pnfsoftware.com\/blog\/?p=521"},"modified":"2017-08-06T10:48:05","modified_gmt":"2017-08-06T18:48:05","slug":"jeb-debuggers-interpreter","status":"publish","type":"post","link":"https:\/\/www.pnfsoftware.com\/blog\/jeb-debuggers-interpreter\/","title":{"rendered":"Advanced Debugger Usage via the Interpreter"},"content":{"rendered":"

This blog is a follow-up to the original debuggers tutorial published here<\/a>. It focuses on the debuggers’ command interpreters<\/strong>, and how to use the new advanced features introduced in JEB 2.2.10<\/a> to make the most out of your live debugging sessions.<\/p>\n

Context<\/h1>\n

When debugging with JEB,\u00a0 you have the standard basic visual options to set\/unset breakpoints, step and 3 tabs that gives some hints on the device being debugged<\/p>\n

\"Debugger<\/a><\/p>\n

So let’s see today a feature that has been newly refreshed: the interpreter. It is available in the Console<\/em> window<\/p>\n

\"Console<\/a><\/p>\n

The first command to learn is help<\/span><\/em><\/strong>: it lists all the available commands. The Console part, as well as the Logger part, is common to all debuggers. So the first step is to select the debugger to work with.<\/p>\n

Type list<\/strong><\/em><\/span> to see available debuggers<\/p>\n

\"interpreters_list\"<\/a><\/p>\n

In this case, we have 2 active debuggers: VM<\/em> (for java code) and Process<\/em> (for native code). Let’s connect to the VM debugger (it is always available when you debug an android project). Type use 1<\/strong><\/em><\/span>. The prompt changes to indicate the current debugger. Use exit<\/span><\/strong><\/em> to go back to root level.<\/p>\n

There are 2 types of commands in the VM interpreter: thread related commands and object interaction commands.<\/p>\n

VM Commands<\/h1>\n

\"interpreter_vm_thread\"<\/a><\/p>\n

Here is a summary of the thread management commands.\u00a0 It consists of a set of debugger basic features that are available in the UI: resume, step, manage breakpoints.<\/p>\n

By pressing enter without any command, you can repeat the same action, which is pretty handy for step actions.<\/p><\/blockquote>\n

 <\/p>\n

But that’s not all, the interpreter has some more powerful commands to manage objects\/classes and interact with them. Let’s take a look at these commands<\/p>\n

\"interpreter_vm_objects\"<\/a><\/p>\n

To get more help on a command, type “help $command$”, there will be a full description of it.<\/p><\/blockquote>\n

Class Commands<\/h2>\n

Now,\u00a0 here is the interesting step: you can retrieve fields<\/strong><\/span><\/em>\/methods<\/em><\/strong><\/span> from a cid<\/strong>. A cid (stands for classId) represents a way to access the class. It can be:<\/p>\n