Mastering Arrays and Strings in Java

What is the default value of an uninitialized integer array in Java?

• 0

• -1

• undefined

• null

How do you declare an array of strings in Java?

• String arrayName[] = new String[size];

• String[] arrayName = new String[size];

• String arrayName = new String[size];

• String[] arrayName = String[size];

What method can be used to find the length of a string in Java?

• Use the size() method of the String class.

• Call the getLength() function on the String object.

• Use the count() method of the String class.

• Use the length() method of the String class.

How do you concatenate two strings in Java?

• You can concatenate two strings using the '-' operator.

• Strings can only be concatenated using the StringBuilder class.

• You must use the String.join() method to concatenate strings.

• You can concatenate two strings in Java using the '+' operator or the String.concat() method.

What is the difference between a one-dimensional array and a multidimensional array?

• A one-dimensional array is always larger than a multidimensional array.

• A one-dimensional array can only be accessed sequentially, while a multidimensional array can be accessed randomly.

• A one-dimensional array can only hold numbers, while a multidimensional array can hold any data type.

• A one-dimensional array is linear, while a multidimensional array can represent data in multiple dimensions.

How do you access the element at the second row and third column of a 2D array?

• array(1,2)

• array[2][3]

• array[1,3]

• array[1][2]

What is the primary advantage of using StringBuilder over String in Java?

• StringBuilder is immutable and safer for multi-threading.

• String is more efficient for concatenation.

• String uses less memory than StringBuilder.

• The primary advantage of using StringBuilder over String in Java is its mutability, which allows for more efficient string manipulation.

How do you convert a String to a character array in Java?

• String str = "example"; char[] charArray = str.toCharArray();

• charArray = new char[str.length()];

• charArray = str.split();

• charArray = str.getChars();

What is the main difference between ArrayList and Array in Java?

• Array is resizable, while ArrayList is fixed-size.

• The main difference is that ArrayList is resizable, while Array is fixed-size.

• ArrayList has a maximum size limit, while Array can grow indefinitely.

• ArrayList can only store primitive types, while Array can store objects.

How do you sort an array of integers in ascending order in Java?

• Arrays.sort(array);

• sort(array)

• Arrays.order(array)

• array.sort()