Technical interview questions and answers are essential for J2SE Interviews because core Java concepts form the foundation of all Java-based development. Companies test your knowledge of OOP principles, exceptions, packages, JVM architecture, threading, collections, and file handling. These topics commonly appear in placement drives and technical interviews conducted by TCS, Infosys, Wipro, Cognizant, and Capgemini. Understanding J2SE concepts helps freshers and job seekers prepare for both Java developer roles and advanced J2EE/Java EE interviews. This guide features the most commonly asked J2SE interview questions with answers explained in simple language. Preparing these questions will strengthen your Java basics and improve your performance in coding tests and technical rounds.
Java programmers should advance their enterprise skills by studying J2EE frameworks and mastering EJB components for distributed applications
Showing 10 of 237 questions
201. What is static field ?
Another name for class variable.
202. What is static method ?
Another name for class method.
203. What is stream ?
A stream is simply a byte-stream of data that is sent from a sender to a receiver. There are two basic categories, so the java.io package includes two abstract classes (InputStream and OutputStream).
204. What is subclass ?
A class that is derived from a particular class, perhaps with one or more classes in between. See also superclass, supertype.
205. What is subtype ?
If type X extends or implements type Y, then X is a subtype of Y. See also supertype.
206. What is superclass ?
A class from which a particular class is derived, perhaps with one or more classes in between. See also subclass, subtype.
207. What is super ?
A Java keyword used to access members of a class inherited by the class in which it appears.
208. What is supertype ?
The supertypes of a type are all the interfaces and classes that are extended or implemented by that type. See also subtype, superclass.
209. What is switch ?
A Java keyword used to evaluate a variable that can later be matched with a value specified by the case keyword in order to execute a group of statements.
210. What is Swing ?
A collection of graphical user interface (GUI) components that runs uniformly on any native platform which supports the Java virtual machine*. Because they are written entirely in the Java programming language, these components may provide functionality above and beyond that provided by native-platform equivalents. (Contrast with AWT.)