Java Basics

What is JDK?

• Java Development Kit

• Java Distribution kit

• Java Dont kit

• Java Dona Kit

What will be the output of the following code? ```java System.out.println(2 + "2" + 2); ```

• 222
• 6
• Error
• 22

Answer explanation

The first 2 is treated as a number, but when concatenated with a string "2", it becomes a string. So the final result is '222'.

What will be the output? ```java System.out.println(10 / 0); ```

• Infinity
• ArithmeticException
• 0
• Compilation Error

Answer explanation

Division by zero using integers throws an ArithmeticException in Java.

What will be the output of the following? ```java for (int i = 0; i < 3; i++) { System.out.print(i + " "); } ```

• 0 1 2
• 0 1 2 3
• 1 2 3
• Infinite loop

Answer explanation

The loop runs while i < 3. It prints 0, 1, and 2, then stops.

What is the output of this? ```java System.out.println("5 + 5 = " + 5 + 5); ```

• 5 + 5 = 10
• 5 + 5 = 55
• Error
• 5 + 5 = 5 + 5

Answer explanation

String concatenation happens first. "5 + 5 = " + 5 is "5 + 5 = 5", then adding another 5 gives "5 + 5 = 55".

What is the output? ```java System.out.println(2 * 3 + "4" + 5); ```

• 645
• 9
• 345
• Error

Answer explanation

2 * 3 is calculated first, giving 6. Then, '6' concatenates with "4" to become "64", and finally adding 5 gives "645".

What will be the output of the following code? ```java System.out.println(2 + "2" + 2); ```

• 222
• 6
• Error
• 22

Answer explanation

The first 2 is treated as a number, but when concatenated with a string "2", it becomes a string. So the final result is '222'.

What will be the output? ```java System.out.println(10 / 0); ```

• Infinity
• ArithmeticException
• 0
• Compilation Error

Answer explanation

Division by zero using integers throws an ArithmeticException in Java.

What will be the output of the following? ```java for (int i = 0; i < 3; i++) { System.out.print(i + " "); } ```

• 0 1 2
• 0 1 2 3
• 1 2 3
• Infinite loop

Answer explanation

The loop runs while i < 3. It prints 0, 1, and 2, then stops.

What is the output of this? ```java System.out.println("5 + 5 = " + 5 + 5); ```

• 5 + 5 = 10
• 5 + 5 = 55
• Error
• 5 + 5 = 5 + 5

Answer explanation

String concatenation happens first. "5 + 5 = " + 5 is "5 + 5 = 5", then adding another 5 gives "5 + 5 = 55".