Adv Java

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 2

11. What is the difference between an Interface and an Abstract class?

  • An abstract class can have instance methods that implement a default behavior.

  • An Interface can only declare constants and instance methods, but cannot implement default behavior and all methods are implicitly abstract.

  • An interface has all public members and no implementation.

  • An abstract class is a class which may have the usual flavors of class members (private, protected, etc.), but has some abstract methods.


12. What is the garbage collection in Java, and when is it used?

  • The purpose of garbage collection is to identify and discard objects that are no longer needed by a program so that their resources can be reclaimed and reused.

  • A Java object is subject to garbage collection when it becomes unreachable to the program in which it is used.


13. Describe synchronization in respect to multithreading?

  • With respect to multithreading, synchronization is the capability to control the access of multiple threads to shared resources. Without synchonization, it is possible for one thread to modify a shared variable while another thread is in the process of using or updating same shared variable. This usually leads to significant errors.


14. Explain different way of using thread?

  • The thread could be implemented by using runnable interface or by inheriting from the Thread class. The former is more advantageous, 'cause when you are going for multiple inheritance..the only interface can help.


15. What are pass by reference and passby value?

  • Pass By Reference means the passing the address itself rather than passing the value. Passby Value means passing a copy of the value to be passed.


16. What is HashMap and Map?

  • Map is Interface and Hashmap is class that implements that.

  • Map: The features of Map interface are the elements should be stored in key/value pairs. Map accepts null values also both as key and value. Map does not accept duplicate keys (if added a duplicate, the earlier one is simply overridden and not a compilation error or exception). These features are inherited by HashMap.

  • The Map and the derived classes of Map are part of collections framework even though Map maintains its separate hierarchy. Map is best suitable to store the properties of a student like name and marks or telephone directory (name and telephone number). Map uses hashing algorithm to return the value when a key is supplied.

  • HashMap: is an implementation of Map. All the properties of Map, discussed earlier, are attained by HashMap. To have the advantage of performance, the HashMap object can be assigned explicitly with initial capacity and load factor.

  • The capacity gives the existing storage capability and the load factor gives increment rate of providing additional capacity when the existing capacity is exhausted.


17. Difference between HashMap and HashTable?

  • The HashMap class is roughly equivalent to Hashtable, except that it is unsynchronized and permits nulls. (HashMap allows null values as key and value whereas Hashtable doesnt allow).

  • HashMap does not guarantee that the order of the map will remain constant over time.

  • HashMap is unsynchronized and Hashtable is synchronized.


18. Difference between Vector and ArrayList?

  • Vector is synchronized whereas arraylist is not.


19. Difference between Swing and Awt?

  • AWT are heavy weight componenets. Swings are light weight components.Hence swing works faster than AWT


20. What is the difference between a constructor and a method?

  • A constructor is a member function of a class that is used to create objects of that class. It has the same name as the class itself, has no return type, and is invoked using the new operator.

  • A method is an ordinary member function of a class. It has its own name, a return type (which may be void), and is invoked using the dot operator.

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