Tag: java

Questions Related to java

Which one of the following is not a valid Javadoc tag?



      

    

    

      
          java

    

    

      
    
          
  1. 
            
    @author
    

          
    2. 
          
  2. 
            
    {@link}
    

          
    3. 
          
  3. 
            
    @serialField
    

          
    4. 
          
  4. 
            
    @arg
    

          
    5. 
      

    

    

    

      

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        Correct Option: D
      

        

          Explanation:
          

            
To answer this question, the user needs to know about Javadoc tags and their purpose in documenting Java code.



Now, let's go through each option and explain why it is right or wrong:



A. @author: This is a valid Javadoc tag that is used to indicate the author of the code or the documentation.



B. {@link}: This is a valid Javadoc tag that is used to create a hyperlink to another class, method, or field in the code documentation.



C. @serialField: This is a valid Javadoc tag that is used to document the fields of a serializable class.



D. @arg: This is not a valid Javadoc tag. The correct Javadoc tag for documenting method arguments is @param.



Therefore, the answer is:



The Answer is: D. @arg


          

        

    

  


    



      

    

      

          
Which one of the following statements about an identifier is incorrect?


      

    

    

      
          java

    

    

      
    
          
  1. 
            
    An identifier can include letters and the first character can be a letter.
    

          
    2. 
          
  2. 
            
    An identifier can include digits, but the first character cannot be a digit.
    

          
    3. 
          
  3. 
            
    An identifier's length can exceed the length of the current line.
    

          
    4. 
          
  4. 
            
    The symbol for PI (3.14159...) is a valid identifier.
    

          
    5. 
      

    

    

    

      

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        Correct Option: C
      

    

  



    

    

      

        
Which one of the following identifiers is not a keyword?


      

    

    

      
            java

    

    

      
    
            
  1. 
              
    null
    

            
    2. 
            
  2. 
              
    transient
    

            
    3. 
            
  3. 
              
    assert
    

            
    4. 
            
  4. 
              
    const
    

            
    5. 
      

    

    

    

      

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        Correct Option: A
      

    

  



      

    

      

          
Which one of the following primitive types is intended for use with Unicode?


      

    

    

      
          java

    

    

      
    
          
  1. 
            
    Double precision floating-point (double)
    

          
    2. 
          
  2. 
            
    Character (char)
    

          
    3. 
          
  3. 
            
    Byte integer (byte)
    

          
    4. 
          
  4. 
            
    Boolean (boolean)
    

          
    5. 
      

    

    

    

      

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        Correct Option: B
      

    

  



      

    

      

          
Which one of the following type-oriented statements is incorrect?


      

    

    

      
          java

    

    

      
    
          
  1. 
            
    User-defined types are also known as reference types.
    

          
    2. 
          
  2. 
            
    User-defined types are only defined via classes and interfaces.
    

          
    3. 
          
  3. 
            
    An array type is signified by an identifier and one or more pairs of square brackets.
    

          
    4. 
          
  4. 
            
    The declaration int[] x; introduces an array type.
    

          
    5. 
      

    

    

    

      

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        Correct Option: B
      

    

  



    

    

      

        
Which one of the following syntactic constructs is not a simple expression?


      

    

    

      
            java

    

    

      
    
            
  1. 
              
    null
    

            
    2. 
            
  2. 
              
    43
    

            
    3. 
            
  3. 
              
    x 2
    

            
    4. 
            
  4. 
              
    print()
    

            
    5. 
      

    

    

    

      

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        Correct Option: C
      

        

          Explanation:
          

            
It's a compound expression consisting of simple expression x (variable name), the addition operator ( ), and simple expression 2 (a 32-bit integer literal).


          

        

    

  


    



    

    

      

        
Which one of the following escape sequences cannot appear in a string literal?


      

    

    

      
            java

    

    

      
    
            
  1. 
              
    \f
    

            
    2. 
            
  2. 
              
    \u
    

            
    3. 
            
  3. 
              
    \"
    

            
    4. 
            
  4. 
              
    \\
    

            
    5. 
      

    

    

    

      

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        Correct Option: B
      

        

          Explanation:
          

            
\u must be followed by four hexadecimal digits and is then known as a Unicode escape sequence.


          

        

    

  



    

    

      

        
Which one of the following is not a widening conversion rule?


      

    

    

      
            java

    

    

      
    
            
  1. 
              
    Short integer to character
    

            
    2. 
            
  2. 
              
    Integer to long integer
    

            
    3. 
            
  3. 
              
    Floating-point to double precision floating-point
    

            
    4. 
            
  4. 
              
    Character to floating-point
    

            
    5. 
      

    

    

    

      

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        Correct Option: A
      

        

          
AI Explanation

          

          

              

                
To answer this question, you need to understand the concept of widening conversions. Widening conversions are conversions that do not result in any loss of data or precision. Let's go through each option to understand why it is correct or incorrect:



Option A) Short integer to character - This option is incorrect because it is a valid widening conversion rule. When a short integer is converted to a character, it is promoted to an int first and then converted to a character.



Option B) Integer to long integer - This option is incorrect because it is a valid widening conversion rule. When an integer is converted to a long integer, it is promoted to a long integer without any loss of data or precision.



Option C) Floating-point to double precision floating-point - This option is incorrect because it is a valid widening conversion rule. When a floating-point value is converted to a double precision floating-point value, it is promoted to a double precision floating-point without any loss of data or precision.



Option D) Character to floating-point - This option is correct because it is not a valid widening conversion rule. Converting a character to a floating-point value is considered a narrowing conversion, as it can result in a loss of data or precision.



Therefore, the correct answer is Option D. This option is not a widening conversion rule because it involves a narrowing conversion.




                
              

          

        

    

  



    

    

      

        
The ?: operator is an example of which kind of operator?


      

    

    

      
            java

    

    

      
    
            
  1. 
              
    Binary
    

            
    2. 
            
  2. 
              
    Prefix
    

            
    3. 
            
  3. 
              
    Postfix
    

            
    4. 
            
  4. 
              
    Infix
    

            
    5. 
      

    

    

    

      

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        Correct Option: D
      

    

  



      

    

      

          
Which one of the following operators offers the fastest way to divide a negative integer by 2 and keep the negative result (e.g., -4/2 equals -2)?


      

    

    

      
          java

    

    

      
    
          
  1. 
            
    /
    

          
    2. 
          
  2. 
            
    %
    

          
    3. 
          
  3. 
            
    >>
    

          
    4. 
          
  4. 
            
    >>>
    

          
    5. 
      

    

    

    

      

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        Correct Option: C