Try to solve the challenge by yourself first!

I got surprised when I saw the bytecode of the above code —

public class JavaChallenge42 {
    public JavaChallenge42() {
    }

    public static void main(String[] args) {…

Try to solve the challenge by yourself first.

Looks pretty simple, but did you know it already?

The answer is —

Got Challenged!

Yes, it’s not Already knew . Not only this, but the following are also true —

1. -0==0.0
2. -0==0
3. -0==0.0D
4. -0==0.0f
5. 0==0.0f
6. 0==0.0D
7. 0==0.0
8. 0.0D==0.0f…

1. NullPointerException
2. Compile-time Error
3. nullJava Challenge

Try to solve the challenge by yourself first.

Surprisingly, It will not throw NullPointerException instead it will print nullJava Challenge . …

1. true
2. false
3. Ambiguitious
4. Compilation Error

Try to solve the challenge by yourself first.

We know that finally block always gets executed unless you are not exiting from the code. So, the answer will be false . But how the compiler will make sure that the…

1. 1
2. 0.9999999999999999
3. 1.0000000000000001
4. 0.9999999999999999D

Try to solve the challenge by yourself first.

The answer should be 1 but that’s not the case the answer is 0.9999999999999999 . Let’s see the bytecode —

public class JavaChallenge38 {
    public JavaChallenge38() {
    }

    public static void main(String[] args) {
        System.out.println(0.9999999999999999D);
    }
}

So, at compile time only all 0.1 will be added, but it’s weird; so many of you will get a question —

Is floating point math broken???

Please go through the following links, it will help you to understand the entire concept —

Thanks. Don’t forget to upvote.

1. 4
2. 3
3. Compilation Error
4. 2

Please try to solve the challenge by yourself first.

When you will compile the above code snippet, you will get —

incompatiable type: possibly loosy conversion from int to byte at line 6

So, how b++ and b+=1 is getting compiled successfully?

Let’s remove line number 6 —

public…

1. Compilation will fail because primitive(int) type can not be null.
2. It will throw NullPointerException.
3. 0

Try to solve the challenge by yourself first.

This seems a pretty simple challenge, the compilation should fail because primitive type data can not be null because the ternary operator will…

1. Compilation Error
2. ClassA
3. ClassB
4. ClassC
5. ClassC can not be cast to ClassB

Try to solve the challenge by yourself first!

It’s clearly 5th option is the answer because classC can not be cast to classB, which will be caused at line number 4, but that is not the case my friend, what happens is line number 4 will be replaced with —

return (ClassA) o; 

So definitely it will not throw ClassCastException because ClassC can be cast to ClassA. Java generics are not reified here, meaning that in compile-time, the generic type information is “lost” and treated as if the code is replaced with the type’s bound or with Object if it doesn’t exist, which basically types erasure concepts.

So the answer will be ClassC .

Thanks for your time.