1. Java-overview 2. Features of Java 3. History of Java 4. HW SW Req for Java SE 7 5. Java Environment Setup 6. Basic Requirement 7. Comments 8. My First Program in Java 9. Line Break 10. Escape Sequences 11. Literals in Java 12. Identifiers in Java 13. Variables in Java 14. Data-Types in Java 15. Declare Variables 16. Reserved Key Words 17. printf() 18. Chained & Embedded state 19. print sum of 2 nos 20. Scanner class 21. print sum & average 22. Area & Perimeter of Rectangle 23. Area Circumference of Circle 24. Prg.for Simple Calculator 25. Operatos in Java 26. Ex. Of Operators 27. Swap two numbers 28. Hierarchy of Operators 29. if( ) statement 30. check +ve,-ve or zero 31. if..else statement 32. check Odd or Even 33. print larger of 2 nos 34. print largest of 3 nos 35. check divisibility 36. check print range 37. for. . . loop statement 38. print series of nos 39. check divisibility 40. print sum of nos 41. print Pyramid 42. prg.for Factorial 43. fill screen 44. prg.for largest/smallest no 45. print reverse no 46. add each digit 47. prg.for sum of series 48. prg.for fibonacci series 49. check Prime nos 50. prg. Prime no from 1 to 100 51. prg.Specified Prime nos 52. while( ) statement 53. do. . While statement 54. break & continue statement 55. switch case statement 56. Array in Java 57. print reverse order using array 58. Ascending/Descending order 59. search no in Array 60. Multidimensional Array 61. String in Java 62. String with spaces 63. print string in reverse 64. prg. to count A,E,I,O,U vowel 65. User defined methods 66. Methods program example 67. General Purpose Programs 68. Loan & EMI calculation prg. 69. Table print prg. 70. Leap year program 71. lower to UPPER case prg. 72. Age Distribution prg. 73. Bank note calculation prg. 74. Simple Interest prg. 75. Compound Interest prg. 76. Simple Depreciation prg. 77. Reducing bal.Depreciation prg. 78. Marksheet prg. 79. Income Tax prg. 80. Time calculator prg. 81. Distance converter prg. 82. Volume Air Calculation prg. 83. Time to fill Water Tank prg. 84. Salary Calculation prg. 85. Total Sale Calculation prg. 86. Male/Female percentage prg. 87. Library Rent prg. 88. Office Expance prg. 89. Total Salary Calculation prg. 90. Profit or Loss prg. 91. Total Profit/Loss prg. 92. Palindrome program 93. Java Interview Part1 94. Java Interview Part2 95. Java Interview Part3 96. Java Interview Part4 97. Java Interview Part5 98. Java Interview Part6 99. Java Interview Part7 100. Java Interview Part8 101. Java Interview Part9 102. Java Interview Part10 103. Java Interview Part11
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JAVA Interview Questions and Answers Part 9


81. Can a abstract class be declared final?

  • Not possible. An abstract class without being inherited is of no use and hence will result in compile time error.


82. What is use of a abstract variable?

  • Variables can't be declared as abstract. only classes and methods can be declared as abstract.


83. Can you create an object of an abstract class?

  • Not possible. Abstract classes can't be instantiated.


84. Can a abstract class be defined without any abstract methods?

  • Yes it's possible. This is basically to avoid instance creation of the class.


85. Class C implements Interface I containing method m1 and m2 declarations. Class C has provided implementation for method m2. Can I create an object of Class C?

  • No not possible. Class C should provide implementation for all the methods in the Interface I. Since Class C didn't provide implementation for m1 method, it has to be declared as abstract. Abstract classes can't be instantiated.


86. Can a method inside a Interface be declared as final?

  • No not possible. Doing so will result in compilation error. public and abstract are the only applicable modifiers for method declaration in an interface.


87. Can an Interface implement another Interface?

  • Intefaces doesn't provide implementation hence a interface cannot implement another interface.


88. Can an Interface extend another Interface?

  • Yes an Interface can inherit another Interface, for that matter an Interface can extend more than one Interface.


89. Can a Class extend more than one Class?

  • Not possible. A Class can extend only one class but can implement any number of Interfaces.


90. Why is an Interface be able to extend more than one Interface but a Class can't extend more than one Class?

  • Basically Java doesn't allow multiple inheritance, so a Class is restricted to extend only one Class. But an Interface is a pure abstraction model and doesn't have inheritance hierarchy like classes(do remember that the base class of all classes is Object). So an Interface is allowed to extend more than one Interface.

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