data structures and backend with java coursera week 1 quiz answers
Array - Practice quiz
1. Which of the following statements is true about arrays in Java?
- Arrays can have elements of different data types.
- Arrays are dynamic in size and can be resized during runtime.
- Arrays in Java always start from index 0.
- Arrays can have negative indices.
2. Which of the following is the correct way to declare and initialize a one-dimensional array in Java?
- int[] arr = {1, 2, 3, 4, 5};
- int arr[] = {1, 2, 3, 4, 5};
- int arr[5] = {1, 2, 3, 4, 5};
- int arr = {1, 2, 3, 4, 5};
3. Which of the following is an array utility class in Java?
- ArrayUtils
- ArrayHelper
- ArrayUtil
- ArrayHandler
4. What is the maximum number of dimensions that an array can have in Java?
- 1
- 2
- 3
- There is no maximum limit, it can have any number of dimensions.
5. How do you access an element in a two-dimensional array in Java?
- arrayName[row][column]
- arrayName[row, column]
- arrayName[row][, column]
- arrayName[column][row]
String - Practice quiz
6. What is the difference between String and StringBuffer classes in Java?
- String is mutable, while StringBuffer is immutable.
- String is immutable, while StringBuffer is mutable.
- Both String and StringBuffer are mutable.
- Both String and StringBuffer are immutable.
7. What is the purpose of the String Pool in Java?
- To store Strings with the same value in a common memory area for better performance and memory utilization.
- To store Strings with different values in a common memory area for better performance and memory utilization.
- To store Strings in a separate memory area for better performance and memory utilization.
- To store Strings in a dynamic memory area for better performance and memory utilization.
8. Which of the following is a difference between String in Java and String in C++?
- In Java, Strings are mutable, while in C++, Strings are immutable.
- In Java, Strings are immutable, while in C++, strings are mutable.
- In Java, Strings are stored on the stack, while in C++, strings are stored on the heap.
- In Java, Strings are stored on the heap, while in C++, strings are stored on the stack.
9. Which of the following is a method of the StringBuffer class in Java?
- append()
- concat()
- reverse()
- split()
10. Which of the following is a difference between StringBuffer and StringBuilder classes in Java?
- StringBuffer is thread-safe, while StringBuilder is not thread-safe.
- StringBuilder is thread-safe, while StringBuffer is not thread-safe.
- Both StringBuffer and StringBuilder are thread-safe.
- Both StringBuffer and StringBuilder are not thread-safe.
