Difference between revisions of "Netbeans/C2/Netbeans-Debugger/English-timed"

| 00:01

|Hii everyone.  

 

| Welcome to the tutorial on '''Netbeans Debugger. '''

|For this demonstration, I am using the Linux Operating System Ubuntu v12.04,

|and Netbeans IDE v7.1.1  

|We all know that '''debugging''' programs can be a rather painstaking task.  

|Hence, knowing a '''debugging''' tool and being familiar with its features can help you save valuable time.  

|This powerful '''debugging''' tool is very useful,  

|In this tutorial we will learn some of the features that the '''Netbeans Debugger''' provides.  

| This tutorial will acquaint you with

|the '''debugging''' window  

|configuring breakpoints

|evaluating expressions  or setting watches

|options for tracing the execution of your program  

| 01:17

|and options to configure the '''debugger''' itself  

|Now Let's get started and '''debug''' this sample code.  

|I will switch to the Netbeans IDE  

|I have already created a Java Application, '''sampleDebug''' in my IDE for this demonstration.  

|This is a small program that initializes three integer values a, b, and c.  

|Then it prints''' 'Hello World!' ''' and the value of 'a'.  

|It also creates a class object ''''SampleClass',''' which has a ''' 'value' ''' integer, as a private integer value.  

|Then, it computes the value of ''' 'b' ''',

| and calls a function to compute the value of c,  

|and prints the values of 'b' and 'c'.  

|To start with the '''debugging''', let us first set the breakpoint.  

|To set a breakpoint, click on the line number.  

|I will set at this line which prints ''' Hello World!'''

|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.  

|When you run the program in the '''debugging''' mode,  

|by clicking on the ''' Debug Project''' button in the toolbar,  

| the execution of the program stops at the line at which the breakpoint is located.  

|So far, 'a's value has been set.  

|You can see that there are some additional windows below the workspace.  

|There is a 'Variables' window that shows a list of variables and their values.  

|So far, only the variable 'a' has been initialized.  

|We can also look at the 'Output' window with the sample '''debug''' output.  

|There is also a  ''' 'Debugger Console' '''' that says that the program hit a breakpoint on line 29 and has stopped there.  

|There is also a ''''Breakpoints' ''' window that tells you that a breakpoint has been set on line number 29.  

|Before proceeding, let us see how to add a watch.  

|For example, let us say I want to watch on the integer value ''' 'aSample'. '''

|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'. '''

|Click on '''OK. '''

|So far ''' 'aSample' ''' has not been created so it says it does not know the value.  

|Once it executes the line we'll know what the variable contains.  

|In a similar way you can also watch and evaluate expressions.  

| Here I'm checking for b=a+10.

|What if I wanted to know what a-4 is.  

|So let me go to the '''Debug''' menu in the menu bar, and select '''Evaluate expression''' option.  

|The ''' 'Evaluate Code' ''' window appears in the workspace.  

|Here I will enter the expression ''' 'a-4'.'''  

|Click on the '''Evaluate Expression button''' here, and in the Variable window, it says ''' 'a-4' '''s value is 6.  

|That should execute only that 1 single line  of the code to print ''' “Hello World”.'''  

| That says, '''Hello World! a is 10. '''

|Now, I want to go into the constructor of the ''' SampleClass.'''  

|To that I can choose the ''' Step Into''' option from the toolbar.  

|Then I can choose ''' Step Over''' and see that the value came inside the constructor call is now set to 10.  

| You can also check that by hovering on the variable.  

|When I Step Over again, we can see that '''this.variable''' is also set to 10.  

|To get out of this function I can either choose '''Continue, Step Over or Step Out.'''  

|And now I'm back to where the function call was made.  

|When I say '''Step-Over''' again, you will notice that '''aSample.value''' is now set to10.   

| Apart from Breakpoints and StepOvers, you can also stop the execution of the program at the line of the cursor.  

|Now from the toolbar, choose the '''Run To Cursor''' option.  

|You can see that it has computed the value of b, as 20.  

|And inside the variable window, it has set 'b' to be 20.  

|Now, I can choose '''Step Over''' again and d's value also gets initialized and becomes 15.  

|Let me choose '''Step Out''' and come back to the function call.  

|So, when we '''Step Over''' and execute that line, 'c' will get a value of 15.  

|We can now check it in the variable window or hover on the variable to check it's value.  

|Now if you want to stop the '''debugging''' session, you can choose the '''Finish Debugger Session''' option from the toolbar.  

|If you want to continue the execution to the next breakpoint you can choose the '''Continue''' option.  

|Once you finish, you can also choose the '''Continue option''' to complete the execution of the remaining program.  

|In the Output window, it shows me the output as: ''' b '''is 20 and '''c''' is 15.  

|Now, this was a quick overview of the options of '''debugging''' on '''netbeans. '''

|If you want any advanced feature settings, you can -

|Go to '''Tools''' menu, click on '''Options''', go to '''Miscellaneous''' option, click on the '''Java Debugger''' tab.  

|Here you can change settings for multi-threaded program breakpoint options.

|Or have filters to decide on which methods you would want to step in.  

|Now to the assignment.

|If not, introduce some errors with the logic or algorithm.  

|Set breakpoints in the code. Usually, you would set a break at the calling point of a function which you suspect has the error.  

|Use '''Step-Into''' to go into the function.  

|Use '''Step-Overs''' to execute the lines and make sure to inspect the values of variables in the variable window.  

|Add some watches to help you identify and correct the error.  

|Step-Out of the method.  

|And finally, Finish the '''debugger''' session and Run your application.  

|In this tutorial, we became familiar with the '''netbeans debugger. '''

|We saw how to set breakpoints and watches.  

|Add expressions which we want to evaluate, while the code is running.  

|Trace execution of a program with '''Step-Into, Step-Over, Step-Out and Run-to-Cursor''' options.  

|Also saw how to configure the '''debugger''' for advanced '''debugging.'''

|Hope this tutorial saves you a lot of time in your testing and '''debugging''' tasks.  

|Watch the video available at the link shown on the screen.  

|If you do not have good bandwidth, you can download and watch it

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|This tutorial has been  contributed by IT for Change