Java Programming: Ultimate Quiz! MCQ

A constructor is a method that initializes an object immediately upon creation. It has the same name as that of class in which it resides

Explanation: Boolean variable can contain only one of two possible values, true and false.

Explanation: static statements are run as soon as class containing then is loaded, prior to any object declaration.

Explanation: Method length() of string class is used to get the length of the object which invoked method length().

Explanation: continue and break are jump statements, and for is an looping statement.

Explanation: To disallow a method from being overridden, specify final as a modifier at the start of its declaration. Methods declared as final cannot be overridden.

Explanation: Exceptional handling is managed via 5 keywords – try, catch, throws, throw and finally.

Explanation: none

Explanation: Statements (1), (2), (3), and (4) are correct. (1) is correct because when a floating-point number (a double in this case) is cast to an int, it simply loses the digits after the decimal.(2) and (4) are correct because a long can be cast into a byte. If the long is over 127, it loses its most significant (leftmost) bits.(3) actually works, even though a cast is not necessary, because a long can store a byte.

The method append() of class StringBuffer is used to concatenate the string representation to the end of the invoking string. This method appends the specified string to the existing string and returns a reference to the modified StringBuffer object. It is commonly used to build longer strings by appending smaller strings together.

Explanation: getBytes() stores the character in an array of bytes. It uses default character to byte conversions provided by the platform.

Explanation: Packages are both naming and visibility control mechanism. We can define a class inside a package which is not accessible by code outside the package.

Explanation: Deserialization is a process by which the data written in the stream can be extracted out from the stream.

Explanation: Number is an abstract/super class containing subclasses Double, Float, Byte, Short, Integer and Long.

Explanation: We can use binary ampersand operator on integers/chars (and it returns an integer) or on booleans (and it returns a boolean).

The correct answer is "Object clone()". This method is a part of the Object class in Java and is used to create a copy or clone of an object. It returns a new object that is a copy of the original object.

Explanation: A class member declared protected becomes private member of subclass.

The method regionMatches() is used to compare a specific region inside a string with another specific region in another string.

Externalization is an interface for control over serialization and deserialization. It allows developers to have more control over the serialization process by implementing the Externalizable interface and providing their own custom serialization logic. This interface provides two methods, writeExternal() and readExternal(), which allow objects to write and read their own state in a customized manner. This is different from the Serializable interface, which provides a default serialization mechanism. FileFilter and ObjectInput are not interfaces for control over serialization and deserialization.

Explanation: The left shift operator shifts all of the bits in a value to the left specified number of times. For each shift left, the high order bit is shifted out and lost, zero is brought in from the right. When a left shift is applied to an integer operand, bits are lost once they are shifted past the bit position 31.