Copy of CSA [06] ArrayLists and String Methods - Lesson 3 - Integer and Double Objects

Multiple Choice

Which of the following is a primitive type in Java?

• int

• alice

• double object

• reference

Multiple Choice

Which of the following is a key difference between primitive types and reference types in Java?

• Primitive types are defined by the user, reference types are predefined by Java.

• Primitive types have a default value of null, reference types have a default value of zero.

• Primitive types store the actual data, reference types store a reference to the data.

• Primitive types can have attributes and behaviors, reference types cannot.

Multiple Select

Which of the following are reasons why storing integer and decimal values as objects can be useful?

• Objects can be used in collections like ArrayList.

• Objects allow for more efficient memory usage than primitives.

• Objects provide methods for manipulation and conversion.

• Objects can be compared using the == operator.

Multiple Choice

Which constants are provided by the Double class to represent infinity in Java?

• NEGATIVE_INFINITY and POSITIVE_INFINITY

• MAX_VALUE and MIN_VALUE

• INFINITY and NAN

• ZERO and ONE

Open Ended

Explain the difference between constructing an Integer object and a Double object in Java. Provide an example for each.

Multiple Select

Select all statements that are true about wrapper classes in Java.

• They allow primitive types to be used as objects.

• They are immutable.

• They can be used to parse strings into numbers.

• They can change their value after creation.

Multiple Choice

Why are Integer and Double objects considered immutable in Java?

• Because their values cannot be changed once created

• Because they can only store primitive types

• Because they are not part of java.lang package

• Because they do not support arithmetic operations

Open Ended

What happens when you add one to the maximum value of an int in Java?

Multiple Choice

What is the range of values that a Java integer can represent?

• -2147483648 to 2147483647

• -1000000000 to 1000000000

• 0 to 4294967295

• -32768 to 32767

Open Ended

Explain the significance of Integer.MIN_VALUE and Integer.MAX_VALUE in Java. How do these constants help prevent errors in programming?

Multiple Choice

Which of the following statements about overflow and underflow errors in Java is correct?

• Overflow occurs when an integer exceeds Integer.MAX_VALUE, and underflow occurs when it goes below Integer.MIN_VALUE.

• Overflow occurs when an integer goes below Integer.MIN_VALUE, and underflow occurs when it exceeds Integer.MAX_VALUE.

• Overflow and underflow errors only happen with double values.

• Overflow and underflow errors do not affect integer calculations.

Multiple Select

Which of the following are true about the Double type in Java?

• It uses 64 bits of space.

• It can represent decimal numbers.

• It has a precision of about 15 decimal places.

• It has a range from -2147483648 to 2147483647.

Multiple Choice

What is a round-off error in Java, and how does it occur when converting a double to an int?

• It is an error caused by converting a double to an int, resulting in loss of precision.

• It is an error caused by dividing by zero.

• It is an error caused by using an uninitialized variable.

• It is an error caused by incorrect syntax.

Multiple Choice

Which of the following statements about autoboxing in Java is correct?

• Autoboxing converts a primitive type to its corresponding wrapper class object automatically.

• Autoboxing converts a wrapper class object to a primitive type automatically.

• Autoboxing is only used for String types.

• Autoboxing requires explicit casting.

Multiple Select

Select all correct statements about unboxing in Java.

• Unboxing converts an object of a wrapper class to its corresponding primitive type.

• Unboxing is performed automatically by the compiler.

• Unboxing only works with the Double class.

• Unboxing requires explicit casting.

Open Ended

What are some methods in the Integer and Double classes that can be used to convert a String to an int or double value?

Open Ended

What are some differences between primitive and reference types?