121. Which of the following is correct error when loading JAR file with duplicate name?

1. 1. java.lang.ClassNotFound

   
   
   

   2. java.io.NullPointerException

   
   
   

   3. java.lang.DuplicateClassError

   
   
   

   4. java.lang.ClassFormatError

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   java.lang.ClassFormatError: Duplicate Name error is thrown when .class file in the JAR contains a class whose class name is different from the expected name.

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122. Which file separator should be used by MANIFEST file?

1. 1. //

   
   
   

   2. /

   
   
   

   3. \

   
   
   

   4. –

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   MANIFEST file uses classes using / file separator.

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123. Which of the following is not true about Java beans?

1. 1. Extends java.io.Serializable class

   
   
   

   2. Implements java.io.Serializable interface

   
   
   

   3. Provides setter and getter methods for its properties

   
   
   

   4. Provides no argument constructor

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   java.io.Serializable is not a class. Instead it is an interface. Hence it cannot be extended.

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124. Which of the following is not an Enterprise Beans type?

1. 1. Stateless

   
   
   

   2. Stateful

   
   
   

   3. Doubleton

   
   
   

   4. Singleton

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   Stateful, Stateless and Singleton are session beans.

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125. What does Liskov substitution principle specify?

1. 1. child class can be substituted by parent class

   
   
   

   2. parent class can be substituted by child class

   
   
   

   3. No classes can be replaced by each other

   
   
   

   4. parent class cannot be substituted by child class

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   Liskov substitution principle states that Objects in a program should be replaceable with instances of their sub types without altering the correctness of that program.

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