What is difference between HashMap and HashTable?
This is most common interview question. This question asked by almost interviewer. There are mainly three points interviewers want from candidates. Both store value as key-value pairs.
The key differences between the two are
1. Hashmap is not synchronized in nature but Hashtable is synchronised.
2. iterator in the HashMap is fail-safe while for the Hashtable isn't.
Fail-safe - “if the Hashtable is structurally modified at any time after the iterator is created, in any way except through the iterator's own remove method, the iterator will throw a ConcurrentModificationException”
3. HashMap permits null values and only one null key, while Hashtable doesn't allow key or value as null.
Core Java Interview Questions
Object Oriented Programming(OOP) Questions and Answers
Collections Interview Questions
Java Exceptions Interview Questions
Java Threads Interview Questions
Collection framework in java interview questions
oops concepts with example in java
Java Serialization Interview Questions
Top 20 Core Java Interview Questions with Answers
String Interview Question in java With Example
synchronization interview questions
Java Reflection Interview question
Java Executor Framework (JDK 1.5) Interview Questions
JDK 1.7 interview Questations and Answers
Java I/O interview question with example