Top JVM Interview Questions (2024)

1. What is JVM?

2. What is the difference between an interpreted and a compiled in JVM?

3. Does JVM is interpret or compile?

4. What is a Virtual Machine?

5. Explain Java Virtual Machine Architecture?

Q: What is JVM?
Ans:

A Java Virtual Machine (JVM) is a virtual machine that allows a computer to run Java programs along with other languages programs that have been compiled to Java bytecode. It adheres to the "write once, run anywhere" principles. The JVM allows you to write Java code on one machine and run it on anywhere on other machine.

Q: What is the difference between an interpreted and a compiled in JVM?
Ans:

The code is first compiled into platform-specific machine code in compiled languages. For Example C and C++ languages. Whereas in interpreted languages, the computer executes the instructions directly without first compiling them. For Example JavaScript and Python languages.

Q: Does JVM is interpret or compile?
Ans:

Java utilizes both approaches means a mix of the interpret and compile .

1. To generate a class file, Java code is first compiled into byte code.
2. The Java Virtual Machine then interprets this class file.
3. The same class file can be run on any JVM on the same or any other platform.

Q: What is a Virtual Machine?
Ans:

A virtual machine is an image/virtualization/mirroring of a computer system in computing. Virtual machines are computer architecture based and provide the capabilities of a physical computer. Their configurations could include special hardware, software, or a combination of the two. Examples : VMWare, VirtualBox

Q: Explain Java Virtual Machine Architecture?
Ans:

The JVM is made up of belows components.

1. Class Loader

   A.java source file is translated into byte code as a .class file when it is compiled. The class loader loads it into main memory when user attempt to utilize it in program.

2. Runtime Memory/Data Area

   It is made up of five components. Method Area, Heap Area, Stack Area, Program Counter (PC) Registers and Native Method Stacks

3. Execution Engine>

   Execution Engine execute the code of each class when the bytecode is loaded into main memory and information are accessible in the runtime data section.

4. Java Native Interface (JNI)

   It specifies a mechanism for the generated bytecode from managed code written in Java or Kotlin to interact with native code written in C/C++.

5. Native Method Libraries

   Libraries created in other programming languages, like C, C++, and assembly, are known as native method libraries. These libraries are often available as.dll or.so files. Through JNI, these native libraries can be loaded.