Netbeans/C2/Netbeans-Debugger/English-timed

Time	Narration
00:01	Hi everyone.
00:02	Welcome to the tutorial on Netbeans Debugger.
00:06	If this is the first time you are using Netbeans, please view the earlier tutorials on the Spoken Tutorial website.
00:14	For this demonstration, I am using the Linux Operating System Ubuntu v12.04
00:21	and Netbeans IDE v7.1.1.
00:26	We all know that debugging programs can be a rather painstaking task.
00:31	Hence, knowing a debugging tool and being familiar with its features can help you save valuable time.
00:39	This powerful debugging tool is very useful,
00:42	especially when you have to code or test large programs.
00:46	In this tutorial, we will learn some of the features that the Netbeans Debugger provides.
00:53	This tutorial will acquaint you with-
00:55	* the debugging window
00:58	* configuring breakpoints
01:00	* evaluating expressions or setting watches
01:04	* options for tracing the execution of your program and
01:17	* options to configure the debugger itself.
01:12	Now, Let's get started and debug this sample code.
01:17	I will switch to the Netbeans IDE.
01:20	I have already created a Java Application, "sampleDebug", in my IDE for this demonstration.
01:27	This is a small program that initializes three integer values 'a', 'b', and 'c'.
01:35	Then it prints 'Hello World!' and the value of 'a'.
01:40	It also creates a class object 'SampleClass' which has a 'value' integer, as a private integer value.
01:52	Then, it computes the value of 'b'
01:55	and calls a function to compute the value of 'c',
02:00	and prints the values of 'b' and 'c'.
02:05	To start with the debugging, let us first set the break-point.
02:09	To set a break point, click on the line number.
02:13	I will set at this line which prints Hello World!
02:18	Notice that the line at which a break-point is set, changes it's colour to pink and is marked by a small square against its line number.
02:28	When you run the program in the debugging mode,
02:31	by clicking on the Debug Project button in the toolbar,
02:35	the execution of the program stops at the line at which the breakpoint is located.
02:41	So far, a's value has been set.
02:45	Hover on it to check it's value.
02:49	It indicates that it's value is 10.
02:52	You can see that there are some additional windows below the workspace.
02:59	There is a 'Variables' window that shows a list of variables and their values.
03:07	So far, only the variable 'a' has been initialized.
03:11	We can also look at the 'Output' window with the sample debug output.
03:17	There is no output yet.
03:19	There is also a 'Debugger Console' ' that says that the program hit a breakpoint on line 29 and has stopped there.
03:28	There is also a 'Breakpoints' window that tells you that a breakpoint has been set on line number 29.
03:36	Before proceeding, let us see how to add a watch.
03:40	For example, let us say I want to watch on the integer value 'aSample'.
03:48	In the 'Variables' window below the workspace, I will double-click on the Enter new Watch option and enter the name of the variable 'aSample.value'.
04:02	Click on OK.
04:06	So far 'aSample' has not been created so it says it does not know the value.
04:12	Once it executes the line we'll know what the variable contains.
04:16	In a similar way you can also watch and evaluate expressions.
04:21	Here I'm checking for b=a+10.
04:25	What if I wanted to know what a-4 is.
04:29	So let me go to the Debug menu in the menu bar, and select Evaluate expression option.
04:37	The 'Evaluate Code' window appears in the workspace.
04:41	Here I will enter the expression 'a-4'.
04:45	Click on the Evaluate Expression button here, and in the Variable window, it says 'a-4' s value is 6.
04:56	Let us now proceed and execute this single line of code.
05:00	To do that, choose the Step-Over button from the toolbar.
05:06	That should execute only that 1 single line of the code to print “Hello World”.
05:12	To see the output, go to the output window and choose the sampleDebug output window
05:17	That says, Hello World! a is 10.
05:22	The program has now stopped at the line to create a SampleClass object.
05:28	Now, I want to go into the constructor of the SampleClass.
05:32	To that I can choose the Step Into option from the toolbar.
05:41	Then I can choose Step Over and see that the value came inside the constructor call is now set to 10.
05:51	You can also check that by hovering on the variable.
05:55	When I Step Over again, we can see that this.variable is also set to 10.
06:03	To get out of this function I can either choose Continue, Step Over or Step Out.
06:11	Let me choose Step-Out to come out of the method.
06:14	And now I'm back to where the function call was made.
06:19	When I say Step-Over again, you will notice that aSample.value is now set to10.
06:27	This is what we were watching for.
06:30	Apart from Breakpoints and StepOvers, you can also stop the execution of the program at the line of the cursor.
06:38	For example, let me go into the function here and set the cursor to be on this line which says d=b-5; .
06:49	Now from the toolbar, choose the Run To Cursor option.
06:54	You will notice that the execution of the program gets into the function and stops at the line where the cursor is located.
07:05	You can see that it has computed the value of b, as 20.
07:10	And inside the variable window, it has set 'b' to be 20.
07:14	Now, I can choose Step Over again and d's value also gets initialized and becomes 15.
07:23	Now, I can either choose to return or completely finish the execution of the program.
07:29	Let me choose Step Out and come back to the function call.
07:36	When you hover on the getC() function, you'll notice that the function has returned a value of 15.
07:43	The variable 'c' has not yet been assigned that value.
07:47	So, when we Step Over and execute that line, 'c' will get a value of 15.
07:55	We can now check it in the variable window or hover on the variable to check it's value.
08:03	Now if you want to stop the debugging session, you can choose the Finish Debugger Session option from the toolbar.
08:12	If you want to continue the execution to the next breakpoint you can choose the Continue option.
08:19	Once you finish, you can also choose the Continue option to complete the execution of the remaining program.
08:25	Let me choose Continue here.
08:27	In the Output window, it shows me the output as: b is 20 and c is 15.
08:34	Now, this was a quick overview of the options of debugging on netbeans.
08:39	If you want any advanced feature settings, you can -
08:42	Go to Tools menu, click on Options, go to Miscellaneous option, click on the Java Debugger tab.
08:53	Here you can change settings for multi-threaded program breakpoint options.
08:59	Or have filters to decide on which methods you would want to step in.
09:07	Now to the assignment.
09:09	As an assignment, take any of your programs, excellent if it has already errors.
09:16	If not, introduce some errors with the logic or algorithm.
09:20	Set breakpoints in the code. Usually, you would set a break at the calling point of a function which you suspect has the error.
09:29	Use Step-Into to go into the function.
09:32	Use Step-Overs to execute the lines and make sure to inspect the values of variables in the variable window.
09:41	Add some watches to help you identify and correct the error.
09:45	Step-Out of the method.
09:48	Continue till you reach the next breakpoint.
09:51	And finally, Finish the debugger session and Run your application.
09:57	In this tutorial, we became familiar with the netbeans debugger.
10:02	We saw how to set breakpoints and watches.
10:06	Add expressions which we want to evaluate, while the code is running.
10:11	Trace execution of a program with Step-Into, Step-Over, Step-Out and Run-to-Cursor options.
10:19	Also saw how to configure the debugger for advanced debugging.
10:24	Hope this tutorial saves you a lot of time in your testing and debugging tasks.
10:30	Watch the video available at the link shown on the screen.
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10:36	If you do not have good bandwidth, you can download and watch it
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10:59	It is Supported by the National Mission on education through ICT, MHRD, Government of India
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11:14	This tutorial has been contributed by IT for Change
11:18	Thank you for joining us.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Sandhya.np14