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Question: Is null a keyword in java?

The null value is not a keyword in java. true and flase are also not
keywords in java. They are reserved words in java language.
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List Of Java Interview Questions:

  1. Can Java thread object invoke start method twice?
  2. Give the list of Java Object class methods.
  3. Can we call servlet destory() from service()?
  4. Can we override static method?
  5. Can you list serialization methods?
  6. What is the difference between super() and this()?
  7. How to prevent a method from being overridden?
  8. Can we create abstract classes without any abstract methods?
  9. How to destroy the session in servlets?
  10. Can we have static methods in interface?
  11. What is transient variable?
  13. What is abstract class or abstract method?
  14. What is default value of a boolean?
  15. When to use LinkedList or ArrayList?
  16. What is daemon thread?
  17. Does each thread in java uses seperate stack?
  18. What is the difference between Enumeration and Iterator?
  19. Find out switch statement output.
  20. Does system.exit() in try block executes finally block?
  21. What is fail-fast in java?
  22. What is final, finally and finalize?
  23. In java, are true and false keywords?
  24. What are the different session tracking methods?
  25. What is the purpose of garbage collection?
  26. What are the types of ResultSet?
  27. What is difference between wait and sleep methods in java?
  28. What is servlet context?
  30. What is race condition?
  31. How to get current time in milli seconds?
  32. How can you convert Map to List?
  33. What is strictfp keyword?
  34. What is System.out in Java?
  35. What is difference between ServletOuptputStream and PrintWriter?
  36. What is java static import?
  37. When to use String and StringBuffer?
  38. What is difference between StringBuffer and StringBuilder?
  39. What is wrapper class in java?
  40. Is Iterator a Class?
  41. What is java classpath?
  42. Can a class in java be private?
  43. Is null a keyword in java?
  44. What is the initial state of a thread when it is started?
  45. What is the super class for Exception and Error?
  46. What is Class.forName()?
  47. Can interface be final?
  48. What is the difference between exception and error?
  49. What is default value of a local variables?
  50. What is local class in java?
  51. Can we initialise uninitialized final variable?
  52. Can we declare abstract method as final?
  53. Can we have finally block without catch block?
  54. What is pass by value and pass by reference?
  55. Can we declare main method as private?
  56. What is the difference between preemptive scheduling and time slicing?
  57. Can non-static member classes (Local classes) have static members?
  58. What are the environment variables do we neet to set to run Java?
  59. Can you serialize static fields of a class?
  60. What is the difference between declaring a variable and defining a variable?
  61. Where can we use serialization?
  62. What modifiers are allowed for methods in an Interface?
  63. What is the purpose of Runtime and System class?
  64. Which one is faster? ArrayList or Vector? Why?
  65. What is the difference between static synchronized and synchronized methods?
  66. What is the order of catch blocks when catching more than one exception?
  68. What is hashCode?
  69. What is the difference between Hashtable and HashMap?
  70. What are the restrictions when overriding a method?
  71. What is the use of assert keyword?
  72. What is adapter class?
  73. What is difference between break, continue and return statements?
  74. What is the difference between while and do-while statements?
  75. When does the compiler provides the default constructor?
  76. Difference between C++ and Java.
  77. Usages of java packages.
  78. What is dynamic class loading?
  79. What happens if you do not provide a constructor?
  80. Difference between shallow cloning and deep cloning of objects?
  81. Can we have interfaces with no defined methods in java?
  82. What is the difference between “==” and equals() method?
  83. How can you create an immutable class in java?
  84. What are access modifiers?
  85. Can we have private constructor in java?
  86. Why do we need generics in java?
  87. What is the difference between a product and a project?
  88. How does substring() method works on a string?
  89. What is the difference between a Java Library and a framework?
  90. Next set of java interview questions
Knowledge Centre
What is abstract class or abstract method?
We cannot create instance for an abstract class. We can able to create instance for its subclass only. By specifying abstract keyword just before class, we can make a class as abstract class.

public abstract class MyAbstractClass{


Abstract class may or may not contains abstract methods. Abstract method is just method signature, it does not containes any implementation. Its subclass must provide implementation for abstract methods. Abstract methods are looks like as given below:

public abstract int getLength();

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