Adv Java
Programming

1. What Is the Java Technology 2. Points to keep in mind for pyramid. 3. Java Pyramid Program on type 1 4. Java Pyramid Program on type 2 5. Java Pyramid Programs on Type 3 6. Java Pyramid Programs on type 4 7. Java Pyramid Programs on type 5 8. Classes and Objects 9. Recursive functions 10. Constructors in Java 11. Method Overloading 12. Constructor Overloading 13. Inheritance in Java 14. Interface in Java 15. Method Overriding and Hiding Method 16. The final keyword 17. Exception Handling 18. Properties, System & Runtime Class in Java 19. Building Java GUI 20. Layout Managers 21. Menu Bar 22. Applets 23. Threading 24. Java Netwoking 25. Programs for Science and Engineer 26. Prg to demonstrate pre and post increment 27. Prg to convert Farenheit to Celsius temperature 28. Prg to convert kilogram to different units 29. Prg to calculate surface area and volume of sphere 30. Prg to calculate frequency 31. Prg to determine co-ordinate points 32. Prg to determine Equilateral, Isosceles or Scalene triangle 33. Prg to demonstrate conditional operator 34. Prg to calculate Final and initial interest amount 35. Prg to separate entered number 36. Prg to examine while loops and conditions 37. Prg to calculate number of year 38. Prg to find Armstrong number or not 39. Prg to find all Armstrong number 40. Prg to find limited Armstrong number 41. Prg to find Armstrong number using user defined function 42. Prg to find frequency of student 43. Prg to find maximum and minimum number 44. Prg to print number triangle 45. Prg to print vertical number triangle 46. Prg to print number triangle 47. Prg to print binary right angle triangle 48. Prg to print * triangle 49. Prg to to print rhombus 50. Prg to print entered number triangle 51. Prg to to find nCr and nPr 52. Prg to enter an element in array 53. Prg to sort number using array 54. Prg to find the position of element in array 55. Prg to find the position of element in array using boolean flag 56. Prg to add one extra element in an array 57. Prg to find the equation of line 58. Prg to find the common element from two array 59. Prg to find the highest scorer 60. Prg to create a square of number 61. Prg to create Pascal triangle 62. Prg to subtraction, multiplication and division using methods and classes 63. Prg to determine salary grade 64. Prg for complex number 65. Prg to calculate area 66. Prg for Greatest Common Divisior 67. Prg for displaying studenta mark sheet 68. Prg for demonstrating inheritance 69. Prg to calculate area of triangle 70. Prg for calculating volume of sphere or hemisphere 71. Prg for demonstrate classes 72. Prg for employee details 73. Prg for demonstrating super and base class 74. Prg for Bank Account 75. Prg for professor and student details 76. Prg for Addition, Multiplication and finding Transpose of two matrix 77. Prg for counting number of words in a string 78. Prg to count number of vowels and consonants in a string 79. Prg to fine number of upper case, lower case, white spaces and digit in a string 80. Prg to fine number of upper case, lower case, white spaces and digit in a string without inbuilt function 81. Prg to arrange a string in alphabetic order 82. Prg to count the number of character occurrence in a string 83. Prg to find the string length and character position 84. Prg for converting first character of word into upper case 85. Prg for demonstrating vectors for manipulating records 86. Prg for manupulting items record using vectors 87. Prg for bank transaction 88. Prg for counting number of days between any two different date 89. Prg for exception handling 90. Prg for throwing exception 91. Prg for exception 92. Prg to throw exception when number is invalid 93. Prg for renaming the current thread 94. Prg for demonstrating strat method of thread 95. Prg to demonstrate sleep and and join method of thread 96. Prg to demonstrate yield method of thread 97. Prg for demonstrating thread in class inheritance 98. Threading program using runnable interface 99. Thread program using sleep 100. Java Applet program for creating fancy round eye 101. Java Applet program for creating fancy face 102. Java Applet program for drawing string 103. Java Applet program for creating fancy face 104. Java Applet program for displaying fancy fonts 105. Java Applet program for drawing and filling rectangle 106. Java Applet program for creating house 107. Java Applet program to show lifecycle of applet 108. Java Applet program for creating polygon 109. Java Applet program for creating rectangle 110. Java Applet program for drawing line 111. Java Applet program for getting applet width and height 112. Interview Question & Answer part 1 113. Interview Question & Answer part 2 114. Interview Question & Answer part 3 115. Interview Question & Answer part 4 116. Interview Question & Answer part 5 117. Interview Question & Answer part 6 118. Interview Question & Answer part 7 119. Interview Question & Answer part 8 120. Interview Question & Answer part 9 121. Interview Question & Answer part 10 122. Interview Question & Answer part 11
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JAVA Interview Questions and Answers Part 4

 

31. Primitive data types are passed by reference or pass by value?

  • Primitive data types are passed by value.

 

32. Objects are passed by value or by reference?

  • Java only supports pass by value. With objects,the object reference itself is passed by value and so both the original reference and parameter copy both refer to the same object.

 

33. What is serialization?

  • Serialization is a mechanism by which you can save the state of an object by converting it to a byte stream.

 

34. Which methods of Serializable interface should I implement?

  • The serializable interface is an empty interface,it does not contain any methods. So we do not implement any methods.

 

35. How can I customize the seralization process? i.e. how can one have a control over the serialization process?

  • Yes it is possible to have control over serialization process. The class should implement Externalizable interface. This interface contains two methods namely readExternal and writeExternal. You should implement these methods and write the logic for customizing the serialization process.

 

36. What is the common usage of serialization?

  • Whenever an object is to be sent over the network, objects need to be serialized. Moreover if the state of an object is to be saved, objects need to be serilazed.

 

37. What is Externalizable interface?

  • Externalizable is an interface which contains two methods readExternal and writeExternal.These methods give you a control over the serialization mechanism. Thus if your class implements this interface, you can customize the serialization process by implementing these methods.

 

38. Does Java provide any construct to find out the size of an object?

  • No there is not sizeof operator in Java. So there is not direct way to determine the size of an object directly in Java.

 

39. Give a simplest way to find out the time a method takes for execution without using any profiling tool?

  • Read the system time just before the method is invoked and immediately after method returns. Take the time difference, which will give you the time taken by a method for execution.

  • To put it in code...

long start = System.currentTimeMillis ();

method ();

long end = System.currentTimeMillis ();

System.out.println ("Time taken for execution is " +(end-start));

 

  • Remember that if the time taken for execution is too small, it might show that it is taking zero milliseconds for execution. Try it on a method which is big enough, in the sense the one which is doing considerable amout of processing.

 

40. What are wrapper classes?

  • Java provides specialized classes corresponding to each of the primitive data types. These are called wrapper classes. They are e.g. Integer, Character, Double etc.

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