R4RIN – MCQs, Mock Tests | Java Java Mcq Question Set 9

Which of these is wrapper for simple data type float?

1. Double
2. double
3. float
4. Float

✅ Correct Answer: 4

Which of the following is method of wrapper Float for converting the value of an object into byte?

1. byte bytevalue()
2. Bytevalue()
3. Byte Bytevalue()
4. bytevalue()

✅ Correct Answer: 1

Which of these methods is used to check for infinitely large and small values?

1. Isinfinite()
2. isInfinite()
3. IsNaN()
4. isNaN()

✅ Correct Answer: 2

Which of the following package stores all the simple data types in java?

1. java.packages
2. util
3. lang
4. java

✅ Correct Answer: 3

Which of these is a wrapper for data type int?

1. Byte
2. Long
3. Both a & b
4. Integer

✅ Correct Answer: 4

Which of the following methods is a method of wrapper Integer for obtaining hash code for the invoking object?

1. Integer hashcode()
2. int hashCode()
3. int hashcode()
4. int hash()

✅ Correct Answer: 2

Which of these is a super class of wrappers Long, Character & Integer?

1. Number
2. Long
3. Float
4. Digits

✅ Correct Answer: 1

Which of these is wrapper for simple data type char?

1. Character
2. Float
3. String
4. Both a & c

✅ Correct Answer: 1

Which of the following is method of wrapper Integer for converting the value of an object into byte?

1. bytevalue()
2. Byte Bytevalue()
3. Bytevalue()
4. byte bytevalue()

✅ Correct Answer: 4

Which of these methods is used to obtain value of invoking object as a long?

1. Long longvalue()
2. long longValue()
3. Long Longvalue()
4. long value()

✅ Correct Answer: 2

Which of these class have only one field �TYPE�?

1. Process
2. Void
3. Runtime
4. System

✅ Correct Answer: 2

Which of the following method of Process class can terminate a process?

1. void destroy()
2. void terminate()
3. void kill()
4. void exit()

✅ Correct Answer: 1

�Standard output variable �out� is defined in which class?

1. Process
2. Void
3. System
4. Runtime

✅ Correct Answer: 3

Which of these class can encapsulate an entire executing program?

1. Process
2. Runtime
3. System
4. Void

✅ Correct Answer: 1

Which of the following is method of System class is used to find how long a program takes to execute?

1. currenttimeMillis()
2. currentTimeMillis()
3. currenttime()
4. currentTime()

✅ Correct Answer: 2

Which of these class holds a collection of static methods and variables?

1. System
2. Void
3. Runtime
4. Process

✅ Correct Answer: 1

Which of these keywords is used to define packages in Java?

1. Pkg
2. Package
3. package
4. pkg

✅ Correct Answer: 3

Which of these is a mechanism for naming and visibility control of a class and its content?

1. Object
2. Interface
3. Packages
4. None

✅ Correct Answer: 3

Which of this access specifies can be used for a class so that its members can be accessed by a different class in the same package?

1. Protected
2. No Modifier
3. Public
4. All of the above

✅ Correct Answer: 4

Which of these access specifiers can be used for a class so that it's members can be accessed by a different class in the different package?

1. Public
2. Private
3. Protected
4. None

✅ Correct Answer: 1

Which of the following is correct way of importing an entire package pkg?

1. Import pkg.
2. Import pkg.*
3. import pkg.
4. import pkg.*

✅ Correct Answer: 4

Which of the following is incorrect statement about packages?

1. A package can be renamed without renaming the directory in which the classes are stored.
2. Package defines a namespace in which classes are stored.
3. Java uses file system directories to store packages.
4. A package can contain other package within it.

✅ Correct Answer: 1

Output : package pkg; class output { public static void main(String args[]) { StringBuffer s1 = new StringBuffer("Hello"); s1.setCharAt(1, x); System.out.println(s1); } }

1. Hexlo
2. xxxxx
3. xello
4. Hxllo

✅ Correct Answer: 4

Which of these class is superclass of String and StringBuffer class?

1. ArrayList
2. java.lang
3. java.util
4. None

✅ Correct Answer: 2

Which of these operators can be used to concatenate two or more String objects?

1. +
2. &
3. ||
4. +=

✅ Correct Answer: 1

Which of these method of class String is used to obtain length of String object?

1. lengthof()
2. Sizeof()
3. get()
4. length()

✅ Correct Answer: 4

Which of these method of class String is used to extract a single character from a String object?

1. charat()
2. charAt()
3. ChatAt()
4. CHARAT()

✅ Correct Answer: 2

Which of these constructors is used to create an empty String object?

1. String()
2. String(void)
3. String(0)
4. None

✅ Correct Answer: 1

Which of these is an an correct statement?

1. StringBuffer class is used to store string in a buffer for later use.
2. String object can point to some other reference of String variable.
3. String objects are immutable, they cannot be changed.
4. None

✅ Correct Answer: 1

Which of these method of class String is used to compare two String objects for their equality?

1. Equals()
2. equals()
3. Isequal()
4. isequal()

✅ Correct Answer: 2

Which of these methods is used to compare a specific region inside a string with another specific region in another string?

1. regionMatches()
2. RegionMatches()
3. regionMatch()
4. match()

✅ Correct Answer: 1

Which of these method of class String is used to check weather a given object starts with a particular string literal?

1. Starts()
2. ends()
3. endsWith()
4. startsWith()

✅ Correct Answer: 4

What is the value returned by unction compareTo() if the invoking string is less than the string compared?

1. value less than zero
2. value greater than zero
3. zero
4. None

✅ Correct Answer: 1

Which of these data type value is returned by equals() method of String class?

1. boolean
2. char
3. int
4. All of the above

✅ Correct Answer: 1

What will s2 contain after following lines of code? String s1 = one; String s2 = s1.concat(two)

1. one
2. two
3. twoone
4. onetwo

✅ Correct Answer: 4

Which of these method of class String is used to remove leading and trailing whitespaces?

1. startsWith()
2. Trim()
3. trim()
4. doTrim()

✅ Correct Answer: 3

What is the value returned by function compareTo() if the invoking string is less than the string compared?

1. value less than zero
2. value greater than zero
3. zero
4. None

✅ Correct Answer: 1

Which of the following statement is correct?

1. replace() method replaces all the characters in invoking string with another character.
2. replace() replace() method replaces last occurrence of a character in invoking string with another character.
3. replace() method replaces only first occurances of a character in invoking string with another character.
4. replace() method replaces all occurrences of one character in invoking string with another character.

✅ Correct Answer: 4

Which of these class is used to create an object whose character sequence is mutable?

1. StringBuffer()
2. String()
3. Both of the mentioned
4. None

✅ Correct Answer: 1

Which of these method of class StringBuffer is used to concatenate the string representation to the end of invoking string?

1. join()
2. append()
3. concat()
4. concatenate()

✅ Correct Answer: 2

Which of these method of class StringBuffer is used to find the length of current character sequence?

1. capacity()
2. Capacity()
3. Length()
4. length()

✅ Correct Answer: 4

What is the string contained in s after following lines of code? StringBuffer s new StringBuffer(Hello); s.deleteCharAt(0);

1. ello
2. llo
3. Hell
4. Hel

✅ Correct Answer: 1

Which of the following statement is correct?

1. reverseall() method reverses all characters.
2. reverse() method reverses all characters.
3. replace() method replaces last occurrence of a character in invoking string with another character
4. replace() method replaces first occurrence of a character in invoking string with another character.

✅ Correct Answer: 2

Which of these method of class StringBuffer is used to extract a substring from a String object

1. SubString()
2. substring()
3. Substring()
4. None

✅ Correct Answer: 2

What will s2 contain after following lines of code? StringBuffer s1 = one; StringBuffer s2 = s1.append(two)

1. one
2. two
3. twoone
4. onetwo

✅ Correct Answer: 4

Which of the following are incorrect form of StringBuffer class constructor?

1. StringBuffer(int size)
2. StringBuffer()
3. StringBuffer(int size , String str)
4. StringBuffer(String str)

✅ Correct Answer: 3

Which of these class can generate an array which can increase and decrease in size automatically?

1. DynamicsList()
2. DynamicList()
3. ArrayList()
4. LinkedList()

✅ Correct Answer: 3

Which of these method can be used to increase the capacity of ArrayList object manually?

1. ensureCapacity()
2. increasecapacity()
3. increaseCapacity()
4. Capacity()

✅ Correct Answer: 1

Which of these method of ArrayList class is used to obtain present size of an object?

1. index()
2. size()
3. capacity()
4. length()

✅ Correct Answer: 2

Which of these methods can be used to obtain a static array from an ArrayList object?

1. Array()
2. toArray()
3. covertArray()
4. covertoArray()

✅ Correct Answer: 1