Core Java Interview Questions and Answers Part 1

By Atul Rai | Last Updated: July 14, 2020 Previous       Next

Q: What do you know about Java?

A: Java is a high-level programming language originally developed by Sun Microsystems and released in 1995. Java runs on a variety of platforms, such as Windows, Mac OS, and the various versions of UNIX.

Q: What are the supported platforms by Java Programming Language?

A: Java runs on a variety of platforms, such as Windows, Mac OS, and the various versions of UNIX/Linux like HP-Unix, Sun Solaris, Redhat Linux, Ubuntu, CentOS, etc.

Q: List any five features of Java?

A: Some features include Object Oriented, Platform Independent, Robust, Interpreted, Multi-threaded.

Q: Why is Java Architectural Neutral?

A: Its compiler generates an architecture-neutral object file format, which makes the compiled code to be executable on many processors, with the presence of Java runtime system.

Q: How Java enabled High Performance?

A: Java uses Just-In-Time compiler to enable high performance. Just-In-Time compiler is a program that turns Java bytecode, which is a program that contains instructions that must be interpreted into instructions that can be sent directly to the processor.

Q: Why Java is considered dynamic?

A: It is designed to adapt to an evolving environment. Java programs can carry an extensive amount of run-time information that can be used to verify and resolve accesses to objects on run-time.

Q: What is Java Virtual Machine and how it is considered in the context of Java’s platform-independent feature?

A: When Java is compiled, it is not compiled into platform specific machine, rather into platform-independent bytecode. This bytecode is distributed over the web and interpreted by Virtual Machine (JVM) on whichever platform it is being run.

Q: List two Java IDE’s?

A: Netbeans, Eclipse, etc.

Q: List some Java keywords(unlike C, C++ keywords)?

A: Some Java keywords are the import, super, finally, etc.

Q: What do you mean by Object?

A: Object is a runtime entity and its state is stored in fields and behavior is shown via methods. Methods operate on an object’s internal state and serve as the primary mechanism for object-to-object communication.

Q: Define class?

A: A class is a blueprint from which individual objects are created. A class can contain fields and methods to describe the behavior of an object.