IBM Backup Administrator Interview Questions and Answers

ArrayList is faster than Vector due to synchronization overhead in Vector.

• ArrayList is not synchronized while Vector is.

• ArrayList is faster as it does not need to acquire a lock before performing operations.

• Vector is thread-safe while ArrayList is not.

• Use Vector when thread safety is required, else use ArrayList for better performance.

Serialization is the process of converting an object into a stream of bytes to store or transmit it over a network.

• Serialization is used to save the state of an object and recreate it later.

• It is commonly used in network communication to transmit data between different systems.

• Serialization can be done in different formats such as XML, JSON, or binary.

• Examples of serialization libraries include Java Serialization, JSON...read more

Finally block is used in exception handling to execute code regardless of whether an exception is thrown or not.

• Finally block is always executed after try and catch blocks.

• It is used to release resources like file handles, database connections, etc.

• It is also used to perform cleanup operations like closing streams, deleting temporary files, etc.

• Finally block can be used without catch block but not vice versa.

• Example: t...read more

JVM is a virtual machine that executes Java bytecode. It provides a runtime environment for Java programs.

• JVM stands for Java Virtual Machine

• It interprets compiled Java code into machine code

• JVM provides memory management, garbage collection, and security

• JVM is platform-independent, allowing Java programs to run on any system with a JVM installed

• Examples of JVM implementations include Oracle's HotSpot and OpenJDK

Hashmap is a data structure that stores key-value pairs and uses hashing to quickly retrieve values.

• Hashmap uses a hash function to map keys to indices in an array.

• Collisions can occur when multiple keys map to the same index, which can be resolved using techniques like chaining or open addressing.

• Retrieving a value from a hashmap is typically an O(1) operation, but worst case can be O(n) if all keys map to the same in...read more

OOPs concepts are the fundamental principles of object-oriented programming.

• Abstraction

• Encapsulation

• Inheritance

• Polymorphism