JAVA CONCEPTS

Important Java Mcq 1

An expression involving byte, int, and literal numbers is promoted to which of these?

a) int

b) long

c) byte

d) float

Answer

a) int

Explanation:

In an expression involving bytes, ints, shorts, or literal numbers, the entire expression is promoted to int before any calculation is done so correct response will be option a (int).

The mechanism of designing a new class based on one or more existing classes is called?

a. Polymorphism b. Inheritance c. Abstraction d. Encapsulation Answer: b. Inheritance Explanation Inheritance in Java is a mechanism in which one object acquires all the

Which component is responsible to optimize bytecode to machine code?

a) JVM b) JDK c) JIT d) JRE Answer: c) JIT Explanation: JIT optimizes bytecode to machine-specific language code by compiling similar bytecodes at the

Type promotion in Java usually refers to ____.

a) Narrowing Type Conversion b) Widening Type Conversion c) No Type Conversion d) None of the above Answer d) Widening Type Conversion

What is the difference between the file MyProgram.java and the file MyProgram.class?

a. MyProgram.java is a compiled executable class file that is run by the computer, and MyProgram.class is a source code file typed by the programmer