To answer this question, let's go through each line of code and understand its behavior:
Integer ten = new Integer(10); - This line creates a new instance of the Integer class and assigns the value 10 to it.
Long nine = new Long(9); - This line creates a new instance of the Long class and assigns the value 9 to it.
System.out.println(ten + nine); - This line attempts to print the sum of ten and nine. Since ten is an Integer and nine is a Long, the Java compiler will try to promote ten to a Long before performing the addition. However, this operation is not supported, and it will result in an error.
int i = 1; - This line declares and initializes an integer variable i with the value 1.
System.out.println(i + ten); - This line attempts to print the sum of i and ten. Since ten is an Integer and i is an int, the Java compiler will automatically promote i to an Integer before performing the addition. The sum will be 1 + 10 = 11, and it will be printed as the output.
Therefore, the correct answer is C. Error: Can't convert java lang Integer. The code will fail to compile because the addition of an Integer and a Long is not supported.