Difference between revisions of "Netbeans/C2/Netbeans-Debugger/English-timed"
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Revision as of 17:59, 9 July 2014
| Time | Narration |
| 00.01 | Hii 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
|
| 01.17 | and 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 breakpoint. |
| 02.09 | To set a breakpoint, 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 breakpoint 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. |
| 10.33 | It summarizes the Spoken Tutorial project. |
| 10.36 | If you do not have good bandwidth, you can download and watch it |
| 10.41 | The Spoken Tutorial project team conduct workshops using Spoken Tutorials.
|
| 10.46 | Gives certificates to those who pass an online test.
|
| 10.49 | For more details contact contact@spoken-tutorial.org
|
| 10.55 | Spoken Tutorial Project is a part of the Talk to a Teacher Project |
| 10.59 | It is Supported by the National Mission on education through ICT, MHRD, Government of India |
| 11.05 | More information on this mission is available at spoken-tutorial.org/NMEICT-Intro |
| 11.14 | This tutorial has been contributed by IT for Change
|
| 11.18 | Thank you for joining us. |
