Type promotion in Java - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable that can hold a decimal number.

Java

double number = [1];

Drag options to blanks, or click blank then click option'

A'a'

B5.5

Ctrue

D100

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning a boolean or character to a double variable.

Assigning an integer without decimal to a double variable (though allowed, the question expects a decimal).

The variable number is declared as double, so it must be assigned a decimal number like 5.5.

2fill in blank

medium

Complete the code to promote an int to a double by assignment.

Java

int i = 10;
double d = [1];

Drag options to blanks, or click blank then click option'

Ai + 0.5

B"10"

Ci

D(double) i + 1.0

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to cast unnecessarily or adding values.

Assigning a string instead of a number.

Assigning an int variable i directly to a double variable d promotes the int to double automatically.

3fill in blank

hard

Complete the code to promote a byte to an int using the correct cast.

Java

byte b = 5;
int i = [1] b;

Drag options to blanks, or click blank then click option'

A(int)

Bdouble

C(byte)

D(char)

Attempts:

3 left

💡 Hint

Common Mistakes

Casting to double or char instead of int.

Casting to byte which is the original type.

To promote a byte to an int, you can cast it explicitly with (int).

4fill in blank

hard

Fill both blanks to create a conditional that promotes a short to int and compares it.

Java

short s = 10;
if ([1] s [2] 5) {
    System.out.println("Greater");
}

Drag options to blanks, or click blank then click option'

A(int)

B>

C<

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong comparison operators.

Not casting before comparison.

The short variable s is promoted to int by casting (int), then compared if greater than 5 using >.

5fill in blank

hard

Fill all three blanks to create a map with keys promoted to uppercase strings and values filtered by condition.

Java

Map<String, Integer> result = Map.of(
    "a", 1,
    "b", 2,
    "c", 3
).entrySet().stream()
 .filter(e -> e.getValue() [1] 1)
 .collect(Collectors.toMap(
    e -> e.getKey()[2],
    e -> e.getValue() [3] 1
));

Drag options to blanks, or click blank then click option'

A>

B.toUpperCase()

C+

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong comparison operators in filter.

Not converting keys to uppercase.

Not incrementing values correctly.

The code filters entries with values greater than 1, promotes keys to uppercase using .toUpperCase(), and increments values by 1.