Top 22 MCQ Questions for JAVA

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1. What is Java?
• A. A high-level programming language
• B. A low-level programming languag e
• C. A database management system
• D. A platform-independent operating system
Answer: A
2. What is the default value of a local variable in Java?
   • A. 0
   • B. null
   • C. undefined
   • D. None of the above
   Answer: C
3. What is the purpose of inheritance in Java?
   • A. To reuse existing code
   • B. To avoid writing new code
   • C. To create new code
   • D. To make code easier to read
   Answer: A
4. What is the difference between an object and a class in Java?
   • A. An object is a blueprint, a class is a prototype
   • B. A class is a blueprint, an object is a prototype
   • C. An object is an instance, a class is a blueprint
   • D. A class is an instance, an object is a blueprint
   Answer: B
5. What is the purpose of packaging in Java?
   • A. To group related classes and interface s together
   • B. To ensure that classes cannot access each other
   • C. To create a separate namespace for c lasses
   • D. To allow classes to be used by other programs
   Answer: A
6. What is the purpose of exceptions in Java?
   • A. To indicate that an error has occurred
   • B. To indicate that a program is com plete
   • C. To indicate that a program has been compiled successfully
   • D. To indicate that a program is r unning
   Answer: A
7. What is the difference between a String and a StringBuilder in Java?
   • A. A String is immutable, a StringBuilder is mutable
   • B. A StringBuilder is immutable, a String is mutable
   • C. A String is a class, a StringBuilder is an interface
   • D. A StringBuilder is a class, a String is an in terface
   Answer: A
8. What is the purpose of threads in Java?
   • A. To improve the performanc e of a program by running multiple tasks simultaneously
   • B. To organize code into a hierarchy of tasks
   • C. To allow a program to run in the background
   • D. To simplify the coding of multi-threaded programs
   A nswer: A
9. What is the purpose of I/O and Streams in Java?
   • A. To read and write data from and t o external sources
   • B. To manipulate data in memory
   • C. To store data in a database
   • D. To trans fer data between programs
   Answer: A
10. What is the purpose of the Core Java Packages?
    • A. To provide a set of standard tools for developing Java programs
    • B. To simplify the coding of complex programs
    • C. To provide a set of standard algorithms for solving common problems
    • D. To provide a set of standa rd data structures for storing data
    Answer: A
11. What is the purpose of the Collection framework in Java?
    • A. To provide a set of classes and interfaces for holding groups of data
    • B. To provide a set of algorithms for searching and sorting data
    • C. To provide a set of classes and interfaces for managing data bases
    • D. To provide a set of classes and interfaces for manipulating text data
    Answer: A
12. What is the default layout manager used by the AWT framework in Java?
    • A. BorderLayout
    • B. FlowLayou t
    • C. GridLayout
    • D. CardLayout
    Answer: B
13. What is the purpose of applets in Jav a?
    • A. To create small, dynamic, graphical applications that can run in a web browser
    • B. To create smal l, static, graphical applications that can run in a web browser
    • C. To create large, dynamic, graphical applic ations that can run on a desktop
    • D. To create large, static, graphical applications that can run on a desktop
    Answer: A
14. What is JDBC in Java?
    • A. Java Database Connectivity, a framework for connec ting to and manipulating databases
    • B. Java Data Backup and Compression, a framework for backing up and compre ssing data
    • C. Java Data Backup and Conversion, a framework for backing up and converting data
    • D. Java Data Backup and Compression, a framework for backing up and compressing databases
    Answer: A
15. What is the difference between a Statement and a PreparedStatement in JDBC?
    • A. A Statement is used for executi ng static SQL statements, a PreparedStatement is used for executing dynamic SQL statements
    • B. A PreparedState ment is used for executing static SQL statements, a Statement is used for executing dynamic SQL statements
    • C. A Statement is used for executing SQL statements, a PreparedStatement is used for executing stored procedures
    D. A PreparedStatement is used for executing SQL statements, a Statement is used for executing stored proceduresAnswer: A
16. What is the difference between a ResultSet and a RowSet in JDBC?
    • A. A ResultSe t is a live database cursor, a RowSet is a disconnected result set
    • B. A RowSet is a live database cursor, a R esultSet is a disconnected result set
    • C. A ResultSet is used for reading data from a database, a RowSet is us ed for updating data in a database
    • D. A RowSet is used for reading data from a database, a ResultSet is used for updating data in a database
    Answer: A
17. What is the purpose of the ResultSetMetaData interf ace in JDBC?
    • A. To retrieve metadata about the columns in a ResultSet
    • B. To retrieve metadata about th e tables in a database
    • C. To retrieve metadata about the data stored in a database
    • D. To retrieve met adata about the structure of a database
    Answer: A
18. What is the difference between inheritance and composition in Java?
    • A. Inheritance allows for code reuse through inheritance of properties and methods fr om a parent class, composition allows for code reuse through composition of objects from other classes
    • B. Com position allows for code reuse through inheritance of properties and methods from a parent class, inheritance allows for code reuse through composition of objects from other classes
    • C. Inheritance and composition both allow fo r code reuse through inheritance of properties and methods from a parent class
    • D. Inheritance and composition both allow for code reuse through composition of objects from other classes
    Answer: A
19. What i s the purpose of exceptions in Java?
    • A. To handle errors and unexpected conditions during program execution
    • B. To validate user input and provide feedback
    • C. To improve the performance of a program
    • D. To provide debugging information
    Answer: A
20. What is the difference between a Thread and a Runnab le in Java?
    • A. A Thread is a concrete implementation of the Thread class, a Runnable is an interface that can be implemented to create a Thread
    • B. A Runnable is a concrete implementation of the Thread class, a Thread is an interface that can be implemented to create a Runnable
    • C. A Thread is an interface that can be implemente d to create a Runnable, a Runnable is a concrete implementation of the Thread class
    • D. A Runnable is an inter face that can be implemented to create a Thread, a Thread is a concrete implementation of the Thread class
    Ans wer: A
21. What is the purpose of streams in Java?
    • A. To allow for efficient reading and writing of data to and from input and output sources
    • B. To allow for efficient processing of data in memory
    • C . To allow for efficient storage of data in a database
    • D. To allow for efficient compression and decompressio n of data
    Answer: A
22. What is the purpose of the core packages in Java?
    • A. To provide ba sic functionality for building Java applications, such as handling strings, reading and writing data, and managing co llections of data
    • B. To provide advanced functionality for building Java applications, such as graphical user interfaces, database connectivity, and networking
    • C. To provide low-level functionality for building Java ap plications, such as memory management and system-level access
    • D. To provide performance optimizations for bui lding Java applications
    Answer: A