Question 1

Which of the following loop headers will arrange for the loop body to execute exactly 10 times?

Accepted Answer

C) starts from -5 and increments up to 4 (inclusive), which is exactly 10 iterations.

Question 2

Which access modifier,used when defining a method,indicates that only one such method is available for all instances of the class?

Accepted Answer

The static access modifier indicates that the method belongs to the class rather than an instance of the class. This means that there is only one instance of the method for all instances of the class. Therefore, option D is the best choice.

Question 3

When using the method System.out.printf( ),what is the purpose of the %d format code?

Accepted Answer

%d format code is used for printing integer values.

Question 4

Suppose c1 and c2 are objects of the class Circle.A Circle has a single data member,its radius.The Circle class has a default constructor (implemented correctly),but no other methods have been defined in the implementation of the Circle class.What will happen when we try to execute this code? Circle c1 = new Circle(12.0);
Circle c2 = new Circle(12.0);
Boolean same = (c1.equals(c2));

Accepted Answer

The equals() method compares objects for equality, and by default, it checks if they refer to the same object in memory. Since c1 and c2 are two different objects, they will not be considered equal, and the value of same will be false. The fact that the Circle class has no additional methods does not affect this behavior.

Question 5

In Java,how do we tell the compiler that the body of a loop consists of several statements,rather than one?

Accepted Answer

To tell the compiler that the body of a loop consists of several statements, we need to enclose the statements in curly braces. This creates a block of code that can have multiple statements. Indenting the statements is only for readability and has no effect on the compiler. Adding all statements on the same line is also only for readability and can also make the code harder to read. Adding a break statement at the end of the loop is not related to indicating that there are multiple statements in the loop body.

Question 6

In order to declare a named constant,the declaration must use which Java keyword?

Accepted Answer

The keyword "final "is used to declare a named constant in Java. Once a variable is declared final, its value cannot be changed throughout the program.

Question 7

Which type of loop is guaranteed to execute its body at least once?

Accepted Answer

The do-while loop is guaranteed to execute its body at least once because the loop condition is evaluated at the end of each iteration. This means that the loop body will always execute at least once, even if the condition is initially false. The other loop types (for, while) evaluate the condition at the beginning, so if the condition is initially false, the loop body will not execute at all.

Question 8

A comment in Java that begins with /** and ends with */ is what kind of comment?

Accepted Answer

A comment in Java that begins with /** and ends with */ is a javadoc comment. These comments are used to automatically generate documentation for software components in the form of HTML files.

Question 9

Suppose a String variable s is initialized to the value "inheritance".What value is returned by the call s.substring(2,5)?

Accepted Answer

The substring method returns a new String that is a substring of the original String. The parameters for the method indicate the starting index (inclusive) and ending index (exclusive) of the desired substring. In this case, s.substring(2,5) will return the characters at index 2, 3, and 4, which are "her". Therefore, the correct answer is C.

Question 10

If s1 is of type String,what does s1.compareTo(s1)return?

Accepted Answer

The method compareTo() compares the value of the string s1 with itself (s1.compareTo(s1)). Since s1 is compared to itself, the output will always be zero. Therefore, the answer is A) zero.

Question 11

What feature of Java transforms class objects into a sequence of bytes that may be used by another program?

Accepted Answer

Serialization in Java is the feature that transforms class objects into a sequence of bytes that can be used by another program. This process allows objects to be sent over a network or saved to a file, making it a very useful feature for Java applications. The other options, such as compilation, inheritance, and tokenization, do not have this capability.

Question 12

What does it mean for the return type of a method to be void?

Accepted Answer

When the return type of a method is void, it means that the method will never return a value. This is typically used for methods that perform actions without needing to return any information or results.

Question 13

What type of Java statement allows you to use classes contained in other packages?

Accepted Answer

An import statement is used in Java to enable the usage of classes that are contained in other packages. It allows a programmer to reference classes from other packages without having to use the fully qualified name of the class every time it is used in the code, which can greatly improve code readability and reduce maintenance efforts.

Question 14

Suppose a try block needs to be followed by two catch blocks,each catching a different exception.Which exception should be caught first?

Accepted Answer

The catch blocks should be ordered from the most specific exception to the most general exception. This is because if the more general exception is caught first, it will handle all exceptions, even the more specific ones that have a specific solution. Catching the more specific exception first ensures that it is handled correctly with the appropriate solution, without the more general exception catching it first.

Question 15

What is the meaning of the declaration: String [][] a = new String [60][80];?

Accepted Answer

The declaration creates a two-dimensional array of strings with 60 rows and 80 columns. The first set of brackets represents the number of rows and the second set of brackets represent the number of columns.

Question 16

How many constructors can a class have?

Accepted Answer

There is no restriction on the number of constructors a class can have. A class can have multiple constructors with different parameter lists to facilitate different ways of initializing the class. Therefore, D is the best choice.

Question 17

Which of the following is an example of a wrapper class?

Accepted Answer

Wrapper classes in Java are used to convert primitive data types into objects. "Double" is a wrapper class for the primitive data type "double".

Question 18

Which of these expressions is illegal in Java?

Accepted Answer

The expression "x++ 5" is illegal in Java because the increment operator "++" cannot be directly followed by a number without an operator in between.

Question 19

Suppose s is of type String.What would it mean if s.lastIndexOf)returns the value 1?

Accepted Answer

If s.lastIndexOf() returns the value 1, it means that the first occurrence of the character at index 1 (the second character) is the last occurrence of that character in the string. This suggests that the first two characters in the string are identical.

Question 20

If x is a variable of type int,what is the largest possible value of the expression (x % 5)?

Accepted Answer

The % operator returns the remainder of division. In this case, it will return a value between 0 and 4 inclusive, which means the largest possible value is 4.

Quiz 1: Review of Java Fundamentals