Java 1

What are the two main types of data types in Java?

• Primitive and Composite
• Primitive and Reference
• Integer and Floating-point
• Static and Dynamic

Answer explanation

Java has primitive data types (e.g., int, boolean) and reference data types (e.g., objects, arrays).

Which of the following is NOT a primitive data type in Java?

• int
• float
• String
• boolean

Answer explanation

String is a reference type, not a primitive.

What is the default value of a reference variable in Java?

• 0
• null
• "" (empty string)
• Undefined

Answer explanation

Reference variables default to null, meaning they do not reference an object until initialized.

What is the size of an int in Java?

• 8 bits
• 16 bits
• 32 bits
• 64 bits

Answer explanation

Java int is always 32-bit signed.

What will System.out.println(10 / 4); print?

• 2
• 2.5
• 3
• 2

Answer explanation

Integer division truncates the decimal, so 10 / 4 results in 2.

What will System.out.println((5 > 3) ? "Yes" : "No"); print?

• Yes
• No
• true
• false

Answer explanation

Since 5 > 3 is true, the ternary operator returns 'Yes'.

What will System.out.println(2 + "3"); print?

• 5
• 23
• 6
• Compilation error

Answer explanation

2 is converted to a string, so '2' + '3' results in '23'.

What will System.out.println("Hello" + 2 + 3); print?

• 5Hello
• Hello23
• Hello5
• Compilation error

Answer explanation

Concatenation starts with a string, so numbers are treated as strings.

What will System.out.println(3 * 2 + 5 * 2); print?

• 10
• 16
• 12
• Compilation error

Answer explanation

Operator precedence: (3*2) + (5*2) = 6 + 10 = 16.

What is the result of System.out.println(10.0 / 4);?

• 2
• 2.5
• 3
• Compilation error

Answer explanation

10.0 is a double, so Java performs floating-point division.