Java interview questions for freshers pdf | Top 100
5 min readFeb 29, 2024
Java interview questions for freshers pdf. Here are the top 100 Java interview questions for freshers.
Java interview questions for freshers pdf — Top 100
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- What is Java, and why is it popular?
- What are the main features of Java?
- Explain the difference between JDK, JRE, and JVM.
- What is the main difference between == and .equals() in Java?
- Explain the concept of object-oriented programming (OOP) in Java.
- What are the four principles of OOP, and why are they important?
- Describe the main components of a Java program.
- What is a class in Java, and how is it used?
- Explain the concept of inheritance in Java with an example.
- What is polymorphism, and how is it implemented in Java?
- Describe the types of polymorphism in Java.
- What is encapsulation, and why is it important in Java?
- Explain the difference between abstract classes and interfaces.
- What are constructors in Java, and how are they used?
- Describe the types of constructors in Java.
- What is method overloading, and how is it implemented in Java?
- Explain the concept of method overriding in Java.
- What are access modifiers, and how do they control access to class members?
- Describe the different types of access modifiers in Java.
- What is the ‘final’ keyword used for in Java?
- Explain the difference between ‘final’, ‘finally’, and ‘finalize’ in Java.
- What is static binding, and how does it differ from dynamic binding?
- Describe the main types of variables in Java.
- What is a static variable, and how is it different from an instance variable?
- Explain the purpose of the ‘this’ keyword in Java.
- What is a package in Java, and how is it used?
- Describe the main types of packages in Java.
- What is the purpose of importing packages in Java?
- Explain the difference between ‘ArrayList’ and ‘LinkedList’ in Java.
- What is the ‘HashMap’ class used for in Java?
- Describe the main features of the ‘HashMap’ class.
- What is the difference between ‘HashSet’ and ‘TreeSet’ in Java?
- What is the ‘Collections’ framework in Java, and why is it used?
- Explain the concept of generics in Java.
- What are the benefits of using generics in Java?
- Describe the main types of exceptions in Java.
- What is the purpose of exception handling in Java?
- Explain the difference between checked and unchecked exceptions.
- Describe the main components of exception handling in Java.
- What is the purpose of the ‘try’, ‘catch’, and ‘finally’ blocks in Java?
- Explain the concept of multi-threading in Java.
- What is a thread, and how is it different from a process?
- Describe the main methods of creating threads in Java.
- What is synchronization, and why is it important in multi-threaded programming?
- Explain the concept of deadlock in Java.
- Describe the main ways to prevent deadlock in Java.
- What is the purpose of the ‘volatile’ keyword in Java?
- Explain the difference between ‘wait()’, ‘notify()’, and ‘notifyAll()’ in Java.
- Describe the main types of garbage collectors in Java.
- What is the purpose of garbage collection in Java?
- Explain the concept of memory management in Java.
- What are the main data types in Java?
- Describe the difference between primitive and reference data types in Java.
- Explain the purpose of autoboxing and unboxing in Java.
- What is type casting, and how is it implemented in Java?
- Describe the main types of operators in Java.
- What is the purpose of conditional statements in Java?
- Explain the difference between ‘if’, ‘else if’, and ‘else’ in Java.
- Describe the main types of loops in Java.
- What is the purpose of the ‘break’ and ‘continue’ statements in Java?
- Explain the concept of arrays in Java.
- Describe the main types of arrays in Java.
- What is the purpose of the ‘length’ property in Java arrays?
- Explain the concept of varargs in Java.
- What is the purpose of the ‘toString()’ method in Java?
- Describe the main types of string manipulation methods in Java.
- Explain the difference between ‘String’, ‘StringBuffer’, and ‘StringBuilder’ in Java.
- What is the purpose of the ‘equals()’ and ‘hashCode()’ methods in Java?
- Describe the main types of sorting algorithms in Java.
- Explain the difference between bubble sort and quicksort in Java.
- What is the purpose of searching algorithms in Java?
- Describe the main types of searching algorithms in Java.
- Explain the purpose of the ‘compareTo()’ method in Java.
- Describe the main types of collection classes in Java.
- What is the purpose of the ‘Comparable’ and ‘Comparator’ interfaces in Java?
- Explain the concept of file handling in Java.
- Describe the main types of file handling operations in Java.
- What is the purpose of the ‘InputStream’ and ‘OutputStream’ classes in Java?
- Explain the concept of serialization and deserialization in Java.
- Describe the main types of input/output streams in Java.
- What is the purpose of the ‘File’ class in Java?
- Explain the concept of networking in Java.
- Describe the main types of network protocols supported by Java.
- What is the purpose of the ‘Socket
- What is the purpose of the ‘Socket’ class in Java networking?
- Explain the difference between TCP and UDP protocols in Java networking.
- What is the purpose of the ‘ServerSocket’ class in Java?
- Describe the main steps involved in creating a client-server application in Java.
- What is the purpose of the ‘URL’ class in Java networking?
- Explain the difference between ‘URLConnection’ and ‘HttpURLConnection’ in Java networking.
- What is the purpose of the ‘URLConnection’ class in Java?
- Describe the main types of exceptions thrown in Java networking.
- What is the purpose of the ‘BufferedReader’ and ‘BufferedWriter’ classes in Java I/O?
- Explain the concept of serialization and deserialization in Java.
- Describe the main steps involved in serializing and deserializing objects in Java.
- What is the purpose of the ‘ObjectInputStream’ and ‘ObjectOutputStream’ classes in Java?
- Explain the difference between ‘FileReader’ and ‘FileWriter’ in Java I/O.
- Describe the main types of streams in Java.
- What is the purpose of the ‘Scanner’ class in Java?
- Explain the concept of exception propagation in Java.