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Sunday, January 17, 2010

Internet Questions for students

61. What is an abstract class?.
A class which cannot be Instantiated.

62.ServletRunner options are:
-p-port number(8080).
-b-backlog connections(50).
-m-maximum no.of connection handlers(100).
-t-connection timeout in milliseconds
-d-servlet directory (current directory)
-s-servlet properties file

63.How many standard ports are available?.

64.What is a policy?.
It's an abstract class for representing the system security policy for a Java application environment(specifying which permissions are available for code from various sources). Java security properties file resides in /lib/security/ directory. Value of "policy.provider" should be changed.

65. What are different ways of Session-Tracking?.
(i) User-Authorization
(ii) Hidden Files
(iii) Persistant Cookies
(iv) URL Rewriting.

66. If the browser does not support cookies or if they are disabled, how is session tracking done?.

Session tracking is done by URL Rewriting.
* Multiple requests can be handled by a servlet and it also can synchronize them.ex: On-line conferencing.
* Servlets have no Graphic User Interface.
* We can synchronize the service() method for a major performance impact as multiple requests are involved in case of servlets.
* We can make a servlet handle a single client/request by implementing single threadmodel interface.

67. What is a Swing?.
It is a GUI component with a pluggable look and feel.

68. What is default Look-and-Feel of a Swing Component?.
Java Look-and-Feel.

69. Awt Components and Swing Components can be inter-mingled in an Application - False

70. What are the features coming with JFC?.
(i) Pluggable Look-and-Feel
(ii) Accessibility API
(iii) Java 2D/API(JDK 1.2).
(iv) Drag and Drop Support(JDK 1.2)

71. What does x mean in javax.swing?.
Extension of java.
72. Images can be displayed on Swing Components
- True
73. Borders can be changed or added for a LightWeight Components
- True
74. Swing Components are always rectangular
- False
75. When Swing components overlap with Heavyweight components, it is the latter that is on the top
- True

76. What are the components which are termed to be Heavy-weight, available in Light-weight component?.

77. What are invisible components?.
They are light weight components that perform no painting, but can take space in the GUI.

78. What is the default layout for a ContentPane in JFC?.

79. What are the borders provided by Swing?.
(i) Simple (ii) Matte iii) Titled iv) Compound.

80. What does Realized mean?.
Realized mean that the component has been painted on screen or that is ready to be painted. Realization can take place by invoking any of these methods.
setVisible(true), show() or pack().

81. What is a convertor?.
Its an application that converts distance measurements between metric and U.S units.

82. What is the return type of interrupt method?. void.
83. What is the superclass of exception?. Throwable.
84. What is servlet exception?. It indicates that there is a problem in the servlet.
85. What is the difference between a Canvas and a Scroll Pane?.
Canvas ScrollPane
Its a component Its a container.
A rectangular area where the application Implements horizontal and vertical
can draw or trap input events. scrolling.
86. What are the restrictions imposed by a Security Manager on Applets?.

i) cannot read or write files on the host that's executing it.
ii) cannot load libraries or define native methods.
iii) cannot make network connections except to the host that it came from
iv) cannot start any program on the host that's executing it.
v) cannot read certain system properties.
vi) windows that an applet brings up look different than windows that an application brings up.

87. Can we access a database using applets?. Yes.
88. What is the default HttpRequest method?. doGet().
89. What is the life cycle of a servlet?.
Removing Handling zero or more client requests.Loading and Initializing.
90. RPC stands for Remote Procedure Call.
91. The three layers in RMI are Application Layer,RemoteReferenceLayer and Network Layer.

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