JAVA Questions
JAVA
What is the purpose of Void class?
The Void class is an uninstantiable placeholder class to hold a reference to the Class object representing the primitive Java type void.
What is reflection?
Reflection allows programmatic access to information about the fields, methods and constructors of loaded classes, and the use reflected fields, methods, and constructors to operate on their underlying counterparts on objects, within security restrictions.
What is the base class for Error and Exception?
Throwable
What is the byte range?
128 to 127
What is the implementation of destroy method in java.. is it native or java code?
This method is not implemented.
What is a package?
To group set of classes into a single unit is known as packaging. Packages provides wide namespace ability.
What are the approaches that you will follow for making a program very efficient?
By avoiding too much of static methods avoiding the excessive and unnecessary use of synchronized methods Selection of related classes based on the application (meaning synchronized classes for multiuser and non-synchronized classes for single user) Usage of appropriate design patterns Using cache methodologies for remote invocations Avoiding creation of variables within a loop and lot more.
What is a DatabaseMetaData?
Comprehensive information about the database as a whole.
What is Locale?
A Locale object represents a specific geographical, political, or cultural region
How will you load a specific locale?
Using ResourceBundle.getBundle(…);
What is JIT and its use?
Really, just a very fast compiler… In this incarnation, pretty much a one-pass compiler — no offline computations. So you can’t look at the whole method, rank the expressions according to which ones are re-used the most, and then generate code. In theory terms, it’s an on-line problem.
Is JVM a compiler or an interpreter?
Interpreter
When you think about optimization, what is the best way to findout the time/memory consuming process?
Using profiler
What is the purpose of assert keyword used in JDK1.4.x?
In order to validate certain expressions. It effectively replaces the if block and automatically throws the AssertionError on failure. This keyword should be used for the critical arguments. Meaning, without that the method does nothing.
How will you get the platform dependent values like line separator, path separator, etc., ?
Using Sytem.getProperty(…) (line.separator, path.separator, …)
What is skeleton and stub? what is the purpose of those?
Stub is a client side representation of the server, which takes care of communicating with the remote server. Skeleton is the server side representation. But that is no more in use… it is deprecated long before in JDK.
What is the final keyword denotes?
final keyword denotes that it is the final implementation for that method or variable or class. You can’t override that method/variable/class any more.
What is the significance of ListIterator?
You can iterate back and forth.
What is the major difference between LinkedList and ArrayList?
LinkedList are meant for sequential accessing. ArrayList are meant for random accessing.
What is nested class?
If all the methods of a inner class is static then it is a nested class.
What is inner class?
If the methods of the inner class can only be accessed via the instance of the inner class, then it is called inner class.
What is composition?
Holding the reference of the other class within some other class is known as composition.
What is aggregation?
It is a special type of composition. If you expose all the methods of a composite class and route the method call to the composite method through its reference, then it is called aggregation.
What are the methods in Object?
clone, equals, wait, finalize, getClass, hashCode, notify, notifyAll, toString
Can you instantiate the Math class?
You can’t instantiate the math class. All the methods in this class are static. And the constructor is not public.
What is singleton?
It is one of the design pattern. This falls in the creational pattern of the design pattern. There will be only one instance for that entire JVM. You can achieve this by having the private constructor in the class. For eg., public class Singleton { private static final Singleton s = new Singleton(); private Singleton() { } public static Singleton getInstance() { return s; } // all non static methods … }
What is DriverManager?
The basic service to manage set of JDBC drivers.
What is Class.forName() does and how it is useful?
It loads the class into the ClassLoader. It returns the Class. Using that you can get the instance ( “class-instance”.newInstance() ).
What is QTP?
Quick Test is a graphical interface record-playback automation tool. It is able to work with any web, java or windows client application. Quick Test enables you to test standard web objects and ActiveX controls. In addition to these environments, Quick Test Professional also enables you to test Java applets and applications and multimedia objects on Applications as well as standard Windows applications, Visual Basic 6 applications and.NET framework applications
What are the Features & Benefits of Quick Test Pro (QTP 8.0)?
Operates stand-alone, or integrated into Mercury Business Process Testing and Mercury Quality Center. Introduces next-generation zero-configuration Keyword Driven testing technology in Quick Test Professional 8.0 allowing for fast test creation, easier maintenance, and more powerful data-driving capability. Identifies objects with Unique Smart Object Recognition, even if they change from build to build, enabling reliable unattended script execution. Collapses test documentation and test creation to a single step with Auto-documentation technology. Enables thorough validation of applications through a full complement of checkpoints.
How to handle the exceptions using recovery scenario manager in QTP?
There are 4 trigger events during which a recovery scenario should be activated. A pop up window appears in an opened application during the test run: A property of an object changes its state or value, A step in the test does not run successfully, An open application fails during the test run, These triggers are considered as exceptions.You can instruct QTP to recover unexpected events or errors that occurred in your testing environment during test run. Recovery scenario manager provides a wizard that guides you through the defining recovery scenario. Recovery scenario has three steps: 1. Triggered Events 2. Recovery steps 3. Post Recovery Test-Run
What is the use of Text output value in QTP?
Output values enable to view the values that the application talks during run time. When parameterized, the values change for each iteration. Thus by creating output values, we can capture the values that the application takes for each run and output them to the data table.
How to use the Object spy in QTP 8.0 version?
There are two ways to Spy the objects in QTP: 1) Thru file toolbar, In the File Toolbar click on the last toolbar button (an icon showing a person with hat). 2) True Object repository Dialog, In Object repository dialog click on the button object spy. In the Object spy Dialog click on the button showing hand symbol. The pointer now changes in to a hand symbol and we have to point out the object to spy the state of the object if at all the object is not visible. or window is minimized then, hold the Ctrl button and activate the required window to and release the Ctrl button.
How Does Run time data (Parameterization) is handled in QTP?
You can then enter test data into the Data Table, an integrated spreadsheet with the full functionality of Excel, to manipulate data sets and create multiple test iterations, without programming, to expand test case coverage. Data can be typed in or imported from databases, spreadsheets, or text files.
What is keyword view and Expert view in QTP?
Quick Test’s Keyword Driven approach, test automation experts have full access to the underlying test and object properties, via an integrated scripting and debugging environment that is round-trip synchronized with the Keyword View. Advanced testers can view and edit their tests in the Expert View, which reveals the underlying industry-standard VBScript that Quick Test Professional automatically generates. Any changes made in the Expert View are automatically synchronized with the Keyword View.
Explain about the Test Fusion Report of QTP?
Once a tester has run a test, a Test Fusion report displays all aspects of the test run: a high-level results overview, an expandable Tree View of the test specifying exactly where application failures occurred, the test data used, application screen shots for every step that highlight any discrepancies, and detailed explanations of each checkpoint pass and failure. By combining Test Fusion reports with Quick Test Professional, you can share reports across an entire QA and development team.
Which environments does QTP support?
Quick Test Professional supports functional testing of all enterprise environments, including Windows, Web,..NET, Java/J2EE, SAP, Siebel, Oracle, PeopleSoft, Visual Basic, ActiveX, mainframe terminal emulators, and Web services.
Explain the QTP Tool interface.?
It contains the following key elements: Title bar, displaying the name of the currently open test, Menu bar, displaying menus of Quick Test commands, File toolbar, containing buttons to assist you in managing tests, Test toolbar, containing buttons used while creating and maintaining tests, Debug toolbar, containing buttons used while debugging tests. Note: The Debug toolbar is not displayed when you open Quick Test for the first time. You can display the Debug toolbar by choosing View — Toolbars — Debug. Action toolbar, containing buttons and a list of actions, enabling you to view the details of an individual action or the entire test flow. Note: The Action toolbar is not displayed when you open Quick Test for the first time. You can display the Action toolbar by choosing View — Toolbars — Action. If you insert a reusable or external action in a test, the Action toolbar is displayed automatically. Test pane, containing two tabs to view your test-the Tree View and the Expert View ,Test Details pane, containing the Active Screen. Data Table, containing two tabs, Global and Action, to assist you in parameterizing your test. Debug Viewer pane, containing three tabs to assist you in debugging your test-Watch Expressions, Variables, and Command. (The Debug Viewer pane can be opened only when a test run pauses at a breakpoint.) Status bar, displaying the status of the test
How does QTP recognize Objects in AUT?
Quick Test stores the definitions for application objects in a file called the Object Repository. As you record your test, Quick Test will add an entry for each item you interact with. Each Object Repository entry will be identified by a logical name (determined automatically by Quick Test), and will contain a set of properties (type, name, etc) that uniquely identify each object. Each line in the Quick Test script will contain a reference to the object that you interacted with, a call to the appropriate method (set, click, check) and any parameters for that method (such as the value for a call to the set method). The references to objects in the script will all be identified by the logical name, rather than any physical, descriptive properties.
What are the types of Object Repositories in QTP?
Quick Test has two types of object repositories for storing object information: shared object repositories and action object repositories. You can choose which type of object repository you want to use as the default type for new tests, and you can change the default as necessary for each new test. The object repository per-action mode is the default setting. In this mode, Quick Test automatically creates an object repository file for each action in your test so that you can create and run tests without creating, choosing, or modifying object repository files. However, if you do modify values in an action object repository, your changes do not have any effect on other actions. Therefore, if the same test object exists in more than one action and you modify an object’s property values in one action, you may need to make the same change in every action (and any test) containing the object.
What is the purpose of Void class?
The Void class is an uninstantiable placeholder class to hold a reference to the Class object representing the primitive Java type void.
What is reflection?
Reflection allows programmatic access to information about the fields, methods and constructors of loaded classes, and the use reflected fields, methods, and constructors to operate on their underlying counterparts on objects, within security restrictions.
What is the base class for Error and Exception?
Throwable
What is the byte range?
128 to 127
What is the implementation of destroy method in java.. is it native or java code?
This method is not implemented.
What is a package?
To group set of classes into a single unit is known as packaging. Packages provides wide namespace ability.
What are the approaches that you will follow for making a program very efficient?
By avoiding too much of static methods avoiding the excessive and unnecessary use of synchronized methods Selection of related classes based on the application (meaning synchronized classes for multiuser and non-synchronized classes for single user) Usage of appropriate design patterns Using cache methodologies for remote invocations Avoiding creation of variables within a loop and lot more.
What is a DatabaseMetaData?
Comprehensive information about the database as a whole.
What is Locale?
A Locale object represents a specific geographical, political, or cultural region
How will you load a specific locale?
Using ResourceBundle.getBundle(…);
What is JIT and its use?
Really, just a very fast compiler… In this incarnation, pretty much a one-pass compiler — no offline computations. So you can’t look at the whole method, rank the expressions according to which ones are re-used the most, and then generate code. In theory terms, it’s an on-line problem.
Is JVM a compiler or an interpreter?
Interpreter
When you think about optimization, what is the best way to findout the time/memory consuming process?
Using profiler
What is the purpose of assert keyword used in JDK1.4.x?
In order to validate certain expressions. It effectively replaces the if block and automatically throws the AssertionError on failure. This keyword should be used for the critical arguments. Meaning, without that the method does nothing.
How will you get the platform dependent values like line separator, path separator, etc., ?
Using Sytem.getProperty(…) (line.separator, path.separator, …)
What is skeleton and stub? what is the purpose of those?
Stub is a client side representation of the server, which takes care of communicating with the remote server. Skeleton is the server side representation. But that is no more in use… it is deprecated long before in JDK.
What is the final keyword denotes?
final keyword denotes that it is the final implementation for that method or variable or class. You can’t override that method/variable/class any more.
What is the significance of ListIterator?
You can iterate back and forth.
What is the major difference between LinkedList and ArrayList?
LinkedList are meant for sequential accessing. ArrayList are meant for random accessing.
What is nested class?
If all the methods of a inner class is static then it is a nested class.
What is inner class?
If the methods of the inner class can only be accessed via the instance of the inner class, then it is called inner class.
What is composition?
Holding the reference of the other class within some other class is known as composition.
What is aggregation?
It is a special type of composition. If you expose all the methods of a composite class and route the method call to the composite method through its reference, then it is called aggregation.
What are the methods in Object?
clone, equals, wait, finalize, getClass, hashCode, notify, notifyAll, toString
Can you instantiate the Math class?
You can’t instantiate the math class. All the methods in this class are static. And the constructor is not public.
What is singleton?
It is one of the design pattern. This falls in the creational pattern of the design pattern. There will be only one instance for that entire JVM. You can achieve this by having the private constructor in the class. For eg., public class Singleton { private static final Singleton s = new Singleton(); private Singleton() { } public static Singleton getInstance() { return s; } // all non static methods … }
What is DriverManager?
The basic service to manage set of JDBC drivers.
What is Class.forName() does and how it is useful?
It loads the class into the ClassLoader. It returns the Class. Using that you can get the instance ( “class-instance”.newInstance() ).
What is QTP?
Quick Test is a graphical interface record-playback automation tool. It is able to work with any web, java or windows client application. Quick Test enables you to test standard web objects and ActiveX controls. In addition to these environments, Quick Test Professional also enables you to test Java applets and applications and multimedia objects on Applications as well as standard Windows applications, Visual Basic 6 applications and.NET framework applications
What are the Features & Benefits of Quick Test Pro (QTP 8.0)?
Operates stand-alone, or integrated into Mercury Business Process Testing and Mercury Quality Center. Introduces next-generation zero-configuration Keyword Driven testing technology in Quick Test Professional 8.0 allowing for fast test creation, easier maintenance, and more powerful data-driving capability. Identifies objects with Unique Smart Object Recognition, even if they change from build to build, enabling reliable unattended script execution. Collapses test documentation and test creation to a single step with Auto-documentation technology. Enables thorough validation of applications through a full complement of checkpoints.
How to handle the exceptions using recovery scenario manager in QTP?
There are 4 trigger events during which a recovery scenario should be activated. A pop up window appears in an opened application during the test run: A property of an object changes its state or value, A step in the test does not run successfully, An open application fails during the test run, These triggers are considered as exceptions.You can instruct QTP to recover unexpected events or errors that occurred in your testing environment during test run. Recovery scenario manager provides a wizard that guides you through the defining recovery scenario. Recovery scenario has three steps: 1. Triggered Events 2. Recovery steps 3. Post Recovery Test-Run
What is the use of Text output value in QTP?
Output values enable to view the values that the application talks during run time. When parameterized, the values change for each iteration. Thus by creating output values, we can capture the values that the application takes for each run and output them to the data table.
How to use the Object spy in QTP 8.0 version?
There are two ways to Spy the objects in QTP: 1) Thru file toolbar, In the File Toolbar click on the last toolbar button (an icon showing a person with hat). 2) True Object repository Dialog, In Object repository dialog click on the button object spy. In the Object spy Dialog click on the button showing hand symbol. The pointer now changes in to a hand symbol and we have to point out the object to spy the state of the object if at all the object is not visible. or window is minimized then, hold the Ctrl button and activate the required window to and release the Ctrl button.
How Does Run time data (Parameterization) is handled in QTP?
You can then enter test data into the Data Table, an integrated spreadsheet with the full functionality of Excel, to manipulate data sets and create multiple test iterations, without programming, to expand test case coverage. Data can be typed in or imported from databases, spreadsheets, or text files.
What is keyword view and Expert view in QTP?
Quick Test’s Keyword Driven approach, test automation experts have full access to the underlying test and object properties, via an integrated scripting and debugging environment that is round-trip synchronized with the Keyword View. Advanced testers can view and edit their tests in the Expert View, which reveals the underlying industry-standard VBScript that Quick Test Professional automatically generates. Any changes made in the Expert View are automatically synchronized with the Keyword View.
Explain about the Test Fusion Report of QTP?
Once a tester has run a test, a Test Fusion report displays all aspects of the test run: a high-level results overview, an expandable Tree View of the test specifying exactly where application failures occurred, the test data used, application screen shots for every step that highlight any discrepancies, and detailed explanations of each checkpoint pass and failure. By combining Test Fusion reports with Quick Test Professional, you can share reports across an entire QA and development team.
Which environments does QTP support?
Quick Test Professional supports functional testing of all enterprise environments, including Windows, Web,..NET, Java/J2EE, SAP, Siebel, Oracle, PeopleSoft, Visual Basic, ActiveX, mainframe terminal emulators, and Web services.
Explain the QTP Tool interface.?
It contains the following key elements: Title bar, displaying the name of the currently open test, Menu bar, displaying menus of Quick Test commands, File toolbar, containing buttons to assist you in managing tests, Test toolbar, containing buttons used while creating and maintaining tests, Debug toolbar, containing buttons used while debugging tests. Note: The Debug toolbar is not displayed when you open Quick Test for the first time. You can display the Debug toolbar by choosing View — Toolbars — Debug. Action toolbar, containing buttons and a list of actions, enabling you to view the details of an individual action or the entire test flow. Note: The Action toolbar is not displayed when you open Quick Test for the first time. You can display the Action toolbar by choosing View — Toolbars — Action. If you insert a reusable or external action in a test, the Action toolbar is displayed automatically. Test pane, containing two tabs to view your test-the Tree View and the Expert View ,Test Details pane, containing the Active Screen. Data Table, containing two tabs, Global and Action, to assist you in parameterizing your test. Debug Viewer pane, containing three tabs to assist you in debugging your test-Watch Expressions, Variables, and Command. (The Debug Viewer pane can be opened only when a test run pauses at a breakpoint.) Status bar, displaying the status of the test
How does QTP recognize Objects in AUT?
Quick Test stores the definitions for application objects in a file called the Object Repository. As you record your test, Quick Test will add an entry for each item you interact with. Each Object Repository entry will be identified by a logical name (determined automatically by Quick Test), and will contain a set of properties (type, name, etc) that uniquely identify each object. Each line in the Quick Test script will contain a reference to the object that you interacted with, a call to the appropriate method (set, click, check) and any parameters for that method (such as the value for a call to the set method). The references to objects in the script will all be identified by the logical name, rather than any physical, descriptive properties.
What are the types of Object Repositories in QTP?
Quick Test has two types of object repositories for storing object information: shared object repositories and action object repositories. You can choose which type of object repository you want to use as the default type for new tests, and you can change the default as necessary for each new test. The object repository per-action mode is the default setting. In this mode, Quick Test automatically creates an object repository file for each action in your test so that you can create and run tests without creating, choosing, or modifying object repository files. However, if you do modify values in an action object repository, your changes do not have any effect on other actions. Therefore, if the same test object exists in more than one action and you modify an object’s property values in one action, you may need to make the same change in every action (and any test) containing the object.
0 Response to "JAVA Questions"
Post a Comment