Java Programming – Classes & Objects – 50+ Solved Q&A on OOP Basics, Constructors, References – CS101 – 2025/2026

This document contains 50+ expertly answered questions on Classes and Objects from the Intro to Java Programming (CS101) course, tailored for the 2025/2026 academic year. It is specifically developed for first-year students in Computer Science, Software Engineering, and IT fields. Whether you’re reviewing for exams, quizzes, or assignments, this pack offers clear, structured insight into the foundational principles of object-oriented programming (OOP) in Java. All questions are paired with accurate and concise answers and reflect real classroom or exam scenarios. The document is also suitable for self-learners or Java beginners needing to understand the core logic of Java objects and memory management. Core topics covered include: State vs. Behavior of Objects Instance Variables and Instance Methods Constructors: Purpose, Declaration, and Use Access Modifiers: public, private Object Instantiation using new Calling Instance Methods Parameters and Arguments Reference Variables and Object Memory Null References and Garbage Collection Accessors (Getters) and Mutators (Setters) Object Immutability Common Methods like toString() String Operations: Concatenation and Trimming Object Cloning and State Copying The content is ideal for: University students enrolled in CS101 or OOP fundamentals Java beginners learning to define and use classes effectively Coding bootcamp students reinforcing their OOP basics OCAJP certification candidates Tutors preparing Java class/object-related quizzes This collection gives students a strong conceptual foundation in Java’s class-based structure, promoting both academic success and industry readiness in object-oriented design. Keywords: Java classes, Java objects, Java OOP, Java constructors, instance variables, instance methods, access modifiers, Java reference variables, Java garbage collection, Java getters, Java setters, object instantiation, CS101 Java, Java toString, Java string methods