What are the differences between arrays and ArrayLists?
Arrays: Fixed size, primitive and object types, `length` property. ArrayLists: Dynamic size, object types only, methods like `add()`, `remove()`, `size()`.
What are the differences between `==` and `.equals()` for Strings?
`==`: Compares object references. `.equals()`: Compares the content of the strings.
What are the differences between `for` and `while` loops?
`for`: Used when the number of iterations is known. `while`: Used when the number of iterations is unknown, and depends on a condition.
What are the differences between method overloading and method overriding?
Overloading: Multiple methods with the same name but different parameters in the same class. Overriding: A subclass providing a different implementation for a method already defined in its superclass.
What are the differences between `x++` and `++x`?
`x++`: Post-increment, returns the original value then increments. `++x`: Pre-increment, increments then returns the new value.
What is the value of `x` after: `int x = 5; x += 3;`?
8
What is the value of `y` after: `int y = 10; y /= 2;`?
5
What is the output of: `String s = "Hello"; System.out.println(s.substring(1, 4));`?
ell
What is the output of: `int[] arr = {1, 2, 3}; System.out.println(arr[1]);`?
2
What is the output of: `ArrayList<String> list = new ArrayList<>(); list.add("A"); System.out.println(list.get(0));`?
A
What is the output of: `int[][] matrix = {{1, 2}, {3, 4}}; System.out.println(matrix[1][0]);`?
3
What is the output: `int x = 5; if (x > 3) System.out.print("A"); else System.out.print("B");`?
A
What is the output: `for(int i = 0; i < 3; i++) System.out.print(i);`?
012
What is wrong with: `String s = "Hello"; s[0] = 'J';`?
Strings are immutable; you cannot change a character at a specific index directly.
What is the output: `int x = 5; System.out.println(x++); System.out.println(x);`?
5
6
What is the output: `int x = 5; System.out.println(++x); System.out.println(x);`?
6
6
What is the output: `String str1 = "hello"; String str2 = new String("hello"); System.out.println(str1 == str2);`?
false
What is the output: `String str1 = "hello"; String str2 = new String("hello"); System.out.println(str1.equals(str2));`?
true
How are arrays applied in real-world scenarios?
Storing lists of data, such as student names, product prices, or sensor readings.
How are ArrayLists applied in real-world scenarios?
Managing a dynamic list of items, such as a shopping cart or a playlist.
How are 2D arrays applied in real-world scenarios?
Representing tables of data, such as spreadsheets, game boards, or image pixels.
How is inheritance applied in real-world scenarios?
Creating a hierarchy of classes, such as different types of vehicles inheriting from a base Vehicle class.
How is recursion applied in real-world scenarios?
Solving problems that can be broken down into smaller, self-similar subproblems, such as searching a file system or parsing a complex data structure.
How are `if` statements applied in real-world scenarios?
Controlling program flow based on conditions, such as validating user input or determining which action to take based on the current state.
How are `for` loops applied in real-world scenarios?
Iterating through a collection of data, such as processing each item in a list or performing an action a specific number of times.
How are `while` loops applied in real-world scenarios?
Repeating an action until a certain condition is met, such as continuously reading data from a sensor until a specific value is reached.
