Tutorial by Examples: debug

Most debugging happens in the terminal or in the Chrome or Safari develop tools, which are plenty sophisticated enough for 99% of your needs. However, if you want to debug on Firefox or need extra server debugging functionality, there are a few extra utilities you can use. Firefox - Firebug Nod...

Some applications that use Hibernate generate a huge amount of SQL when the application is started. Sometimes it's better to enable/disable the SQL log in specific points when debugging. To enable, just run this code in your IDE when you are debugging the aplication: org.apache.log4j.Logger.getLog...

WinDbg is often used as an abbreviation of "Debugging tools for Windows". It contains different debuggers: DebuggerDescriptionWinDbgthe debugger with a graphical user interfaceCDBconsole debugger, user mode debugger which runs in the currently open consoleNTSDnew terminal symbolic debugge...

It is possible to use IO.inspect/1 as a tool to debug an elixir program. defmodule MyModule do def myfunction(argument_1, argument_2) do IO.inspect(argument_1) IO.inspect(argument_2) end end It will print out argument_1 and argument_2 to the console. Since IO.inspect/1 returns i...

Debugging is a very powerful way to have a closer look and fix incorrectly working (or non working) code. Run code step by step First thing you need to do during debugging is to stop the code at specific locations and then run it line by line to see whether that happens what's expected. Breakp...

There are several to evaluate a certain expression when debugging a Java application. 1. Manually inspecting an expression When the program execution is suspended at a certain line (either due to a breakpoint or manually stepping through the debugger), you can manually evaluate an expression by se...

n order to debug a remote Java application, it should be launched with some extra arguments to instruct the JVM to execute it in debug mode. This is done as follows: java -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8000 -jar sampleApp.jar The above command tells the JVM to s...

Add the following dependencies to your application. compile 'com.facebook.stetho:stetho:1.5.0' compile 'com.facebook.stetho:stetho-okhttp3:1.5.0' In your Application class' onCreate method, call the following. Stetho.initializeWithDefaults(this); When creating your Retrofit instance, crea...

A SIGABRT or an EXC_BAD_INSTRUCTION usually means the app crashed itself intentionally because some check failed. These should log a message to the debugger console with more information; check there for more information. Many SIGABRTs are caused by uncaught Objective-C exceptions. There are a lo...

EXC_BAD_ACCESS means the process tried to access memory in an invalid way, like dereferencing a NULL pointer or writing to read-only memory. This is the hardest kind of crash to debug, because it usually does not have an error message, and some crashes can be very difficult to reproduce and/or occu...

Scope testing & output of model <div ng-app="demoApp" ng-controller="mainController as ctrl"> {{$id}} <ul> <li ng-repeat="item in ctrl.items"> {{$id}}<br/> {{item.text}} </li> ...

You can set any function for debugging with debug. debug(mean) mean(1:3) All subsequent calls to the function will enter debugging mode. You can disable this behavior with undebug. undebug(mean) mean(1:3) If you know you only want to enter the debugging mode of a function once, consider t...

Launch debug by clicking on the "beetle" icon: Debug window is now waiting instructions for next step: You can go to the next step by clicking F9 in the debug window or by clicking on the green arrow:

Usage Sometimes, you could have to debug code in another PhpStorm project, you have to update the configuration. PHP configuration In php.ini, edit file and put xdebug.remote_autostart = 1 PhpStorm configuration You also have to configure your IDE: In the phpStorm configuration, Max. sim...

Most basic Django debugging tool is pdb, a part of Python standard library. Init view script Let's examine a simple views.py script: from django.http import HttpResponse def index(request): foo = 1 bar = 0 bug = foo/bar return HttpResponse("%d goes here." % ...

First, you need to install django-debug-toolbar: pip install django-debug-toolbar settings.py: Next, include it to project's installed apps, but be careful - it's always a good practice to use a different settings.py file for such development-only apps and middlewares as debug toolbar: # If en...

You can start the remote debugging from Developer menu. After selecting the enable remote debugging it will open Google Chrome, So that you can log the output into your console. You can also write debugger syntax into your js code.

So your query has failed (see MySQLi connect for how we made $conn) $result = $conn->query('SELECT * FROM non_existent_table'); // This query will fail How do we find out what happened? $result is false so that's no help. Thankfully the connect $conn can tell us what MySQL told us about the f...

debug() and debugonce() won't work well in the context of most Shiny debugging. However, browser() statements inserted in critical places can give you a lot of insight into how your Shiny code is (not) working. See also: Debugging using browser() Showcase mode Showcase mode displays your app alo...

Building project dependencies can sometimes be a tedious task. Instead of publishing a package version to NPM and installing the dependency to test the changes, use npm link. npm link creates a symlink so the latest code can be tested in a local environment. This makes testing global tools and proje...