Unboxing in Java - Interactive Code Practice

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Practice - 5 Tasks

1fill in blank

easy

Complete the code to unbox the Integer object to an int primitive.

Java

Integer num = 10;
int value = num[1];

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

A.toString()

B.valueOf()

C.intValue()

D.doubleValue()

Attempts:

3 left

2fill in blank

medium

Complete the code to assign the unboxed Double value to a double variable.

Java

Double d = 5.5;
double val = d[1];

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

A.toString()

B.intValue()

C.floatValue()

D.doubleValue()

Attempts:

3 left

3fill in blank

hard

Fix the error in unboxing the Boolean object to a boolean primitive.

Java

Boolean flag = Boolean.TRUE;
boolean isTrue = flag[1];

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

A.booleanValue()

B.intValue()

C.toString()

D.doubleValue()

Attempts:

3 left

4fill in blank

hard

Fill both blanks to unbox the Character object and compare it to a char literal.

Java

Character ch = 'a';
if (ch[1] == '[2]') {
    System.out.println("Match");
}

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

A.charValue()

Ba

Cb

D.toString()

Attempts:

3 left

5fill in blank

hard

Fill all three blanks to create a map with unboxed keys and values from wrapper objects.

Java

Map<Integer, Double> map = new HashMap<>();
Integer key = 1;
Double value = 2.5;
map.put(key[1], value[2]);

for (Map.Entry<Integer, Double> entry : map.entrySet()) {
    int k = entry.getKey();
    double v = entry.getValue();
    System.out.println(k [3] v);
}

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

A.intValue()

B.doubleValue()

C+

D-

Attempts:

3 left