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
121. What is Java Naming and Directory Interface (JNDI) ?
A set of APIs that assists with the interfacing to multiple naming and directory services.
122. What is Java Native Interface ?
A standard programming interface for writing Java native methods and embedding the JVM into native applications. The primary goal is binary compatibility of native method libraries across all JVM implementations on a given platform.
123. What is Java Platform ?
Consists of class libraries, a Java virtual machine (JVM) and class loader (which comprise the runtime environment) and a compiler, debugger and other tools (which comprise the development kit). In addition, the runtime platform is subject to a set of compatibility requirements to ensure consistent and compatible implementations. Implementations that meet the compatibility requirements may qualify for Sun's targeted compatibility brands. Java 2 is the current generation of the Java Platform.
124. What is Java Remote Method Invocation (RMI) ?
A distributed object model for Java program to Java program, in which the methods of remote objects written in the Java programming language can be invoked from other Java virtual machines1, possibly on different hosts.
125. What is Java Runtime Environment (JRE) ?
A subset of the Java Development Kit (JDK) for end-users and developers who want to redistribute the runtime environment alone. The Java runtime environment consists of the Java virtual machine1, the Java core classes, and supporting files.
126. What is Java virtual machine ?
A software "execution engine" that safely and compatibly executes the byte codes in Java class files on a microprocessor (whether in a computer or in another electronic device).
127. What is JavaBeans ?
A portable, platform-independent reusable component model. A component that conforms to this model is called a bean.
128. What is JavaCheck ?
A tool for checking compliance of applications and applets to a specification.
129. What is JavaSafe ?
A tool for tracking and managing source file changes, written in Java.
130. What is JavaScript ?
A Web scripting language that is used in both browsers and Web servers. Like all scripting languages, it is used primarily to tie other components together or to accept user input.