Java Fundamentals

What are the different data types in Java?

• apple, banana, orange, grape

• true, false, null, undefined

• int, float, double, char, boolean, and more

• string, array, object, date

Explain the difference between int and double data types in Java.

• int is used for text values, while double is used for numerical values.

• int stores integer values, while double stores floating-point numbers.

• int stores floating-point numbers, while double stores integer values.

• int and double are the same data type in Java.

What is the use of the 'final' keyword in Java?

• To restrict the user from modifying the value of a variable, making it a constant.

• To automatically initialize the variable with a default value

• To make the variable invisible to other classes

• To allow the user to modify the value of a variable freely

What are the different types of operators in Java?

• Comparison, Equality, Inequality

• Addition, Subtraction, Multiplication, Division

• Arithmetic, Relational, Logical, Bitwise, Assignment, Ternary

• If, Else, Switch

What is the difference between '==' and 'equals()' in Java?

• == operator compares reference, equals() method compares content

• equals() and == are interchangeable in Java

• equals() compares reference, == operator compares content

• == operator is used for strings, equals() is used for integers

Explain the concept of increment and decrement operators in Java.

• The increment operator is denoted by 'inc' and the decrement operator is denoted by 'dec'

• The increment operator is denoted by '+' and the decrement operator is denoted by '-'

• The increment operator is denoted by '+=1' and the decrement operator is denoted by '-=1'

• The increment operator is denoted by '++' and the decrement operator is denoted by '--'.

What is the result of the expression '5 + 3 * 2' in Java?

• 11

• 15

• 10

• 7

How are strings concatenated in Java?

• ++ operator

• + operator

• concat() method

• add() method

Explain the concept of type casting in Java.

• Type casting in Java is the process of converting a variable from one data type to the same data type.

• Type casting in Java is the process of converting a variable from one data type to a completely unrelated data type.

• Type casting in Java is the process of converting a variable from one data type to a string.

• Type casting in Java is the process of converting a variable from one data type to another.

What is the use of the 'instanceof' operator in Java?

• To compare two objects for equality

• To convert an object to a different class

• To check if an object is an instance of a particular class or interface.

• To check if a variable is null