Primitive to object conversion in Java - Practice Problems & Coding Challenges

trophy

Challenge - 5 Problems

💻 code output

intermediate

Output of autoboxing with Integer

What is the output of this Java code snippet?

Java

Integer a = 1000;
Integer b = 1000;
System.out.println(a == b);

A true

B false

C Compilation error

D Runtime exception

💻 code output

intermediate

Unboxing and arithmetic with Integer and int

What is the output of this Java code?

Java

Integer x = 5;
int y = 10;
System.out.println(x + y);

A 15

B Compilation error

C 5 10

D NullPointerException

🔧 debug

advanced

Identify the error in primitive to object conversion

Which option will cause a compilation error in this code snippet?

Java

Double d = 10.5;
Integer i = d;

A Double d = 10.5; Integer i = (int) d.doubleValue();

B Double d = 10.5; Integer i = d.intValue();

C Double d = 10.5; int i = d.intValue();

D Double d = 10.5; Integer i = d;

📝 syntax

advanced

Correct way to convert int to Integer

Which option correctly converts a primitive int to an Integer object?

A Integer obj = (Integer) 5;

B Integer obj = 5;

C Integer obj = Integer.valueOf(5);

D Integer obj = new Integer(5);

🚀 application

expert

Predict the output with mixed primitive and wrapper types

What is the output of this Java code?

Java

Integer a = 127;
Integer b = 127;
Integer c = 128;
Integer d = 128;
System.out.println(a == b);
System.out.println(c == d);

A

true
false

B

false
false

C

true
true

D

false
true