Category Archives: Vs

Maven Vs Gradle

Gradle is a built tool developed over Maven and Ant. It’s having lots of differences when compared with Maven.

See Also:

Maven Gradle
Maven uses XML Gradle doesn’t use XML
Maven written in Java Gradle written in Java, Kotlin and Gradle
Maven scripts are not shorter and clean Gradle Scripts are shorter and clean
Maven is a software project management and builds tool developed for Java-based applications. Gradle is an open-source, build automation system built on concepts of maven and ant.
Maven makes build process easier, provides best guidelines for development and allow to migrate new features Gradle allows structuring of build and supports for multi projects builds. Gradle increases productivity provides ways to migrate and builds applications.

Maven Vs Ant

Ant was the first “modern” java application build tool released in 2000. It was famous in a short time because easy to learn, based on procedural programming and not required any additional preparation.

Ant was having some issues in terms of, build time, performance and big scripts and other problems of developers.

Maven releases in 2004 which covers all the problems of Ant and having a complete life cycle.

See Also:

Maven vs Ant

Here are some main differences between Maven and Ant build tool.

Ant Maven
Ant required build script per project. Maven describes the project over configuration.
Ant invoke project-specific targets Maven invoke defined goals (target)
Ant is for “just” build process Maven required knowledge of the project.
Ant scripts are too complex. Maven creates standard project layout and builds in the lifecycle.
Ant scripts are not reusable. Maven plugins and repository are reusable.



RDBMS is extension of DBMS.

DBMS (Database Management System)

Software that provides a systematic way of creating, retrieving and managing data in a database.

DBMS Example : File System, XML, Dbase, Microsoft Access, LibreOffice Base, Fox Pro etc.

RDBMS(Relational Database Management Information System)

A DBMS based on relational model and store data in tables that related to each other.

RDBMS Example: MySQL, PostGre, SQL Server, Oracle, MariaDB, SqlLite etc.

Here area some main points that make differences between DBMS and RDBMS.

DBMS application stores data in files that have no relationship. RDBMS application stores data in tabular form which will have a relation between tables.
DBMS store data either in hierarchical form or navigational form. RDBMS table has one identifier called as primary key and data stored in tabular form.
DBMS does not support Normalization. RDBMS supports normalization.
DBMS does not provide any security with regards to data manipulation. RDBMS defines the integrity constraints for the purpose of ACID property.
DBMS does not support distributed database. RDBMS support distributed database.
DBMS is for small organization to deal with small data. It supports for single user. RDBMS is designed to handle large amount of data. It supports multiple users.
DBMS does not support client server architecture. RDBMS  support client server architecture.
DBMS have high data redundancy. RDBMS have low data redundancy.
DBMS takes more time to access data. RDBMS takes less time to access data.

ACID Vs BASE for Database Transactions

In the previous post, you have learned about the ACID and BASE properties of database transactions in detail.


Here you will know about high-level differences between ACID and BASE.


Provides Vertical Scaling Provides Horizontal Scaling
Strong Consistency Weak Consistency – Stale Data OK
Isolation Last Write Wins, availability first
Transaction Programmer Managed
Available/Consistent Available/Partition Tolerant
Robust Database/Simple Code Simpler Database, Harder Code
Focus on “Commit” Best Effort
Nested Transactions Approximated Answers
Less Availability Aggressive (optimistic)
Conservative (pessimistic) Simpler
Difficult Evaluation(i.e Schema) Faster, Easier evolution
High Maintenance Cost Low Maintenance Cost
Expensive Joins and Relationship Free from joins and Relationship
Examples: Oracle, MySQL, SQL Server, etc. Example : DynamoDB, Cassandra, CouchDB, SimpleDB etc.

See Also:


In this post you will know about the main high level difference between SQL and NoSQL type databases.


Relational Type Non-Relational Type
Structured Data Stored in Tables The un-structured data store in JSON format in file but graph of database show relationship.
Strict Schema Dynamic Schema
Vertical Scalable Horizontal Scalable
Structured Query Language Un-structured Query Language
ACID Transactions CAP Theorem
Requires downtime In most cases automatic, No outage required
Rigid schema bound to the relationship Non-rigid schema and flexible.
Helpful to design complex queries. No joins relationship, no any powerful tool to prepare complex queries.
Recommend and best suited for OLTP (Online Transactional Processing) Systems. Less likely to be considered for the OLTP System.
Storage : Table (Row->Entity, Column->Attribute)
RDBMS: Oracle, MYSQL, SQL Server, IBM DB2 etc.
Key-Value: Redis, Dynamo
Document: MongoDB
Graph: Neo4j, InfiniteGraph
Wide-column- Cassandra, HBASE
SQL is not fit for Hierarchical work. NoSQL is the best fit for hierarchical work as it follows the key-value pair’s way to store values.

Java: Arrays vs Collections

In Java, Arrays and Collections both are to deal with a group of objects but there are lots of differences in terms of data structure or performing operations.

Here are some most common differences:

Difference between Arrays & Collections

Arrays Collections
Arrays is having fixed-length.. Collections are growable in nature i.e increase or decrease.
Arrays are not recommended in terms of memory concerns. Collections use different data structures and recommended to use with respect to memory.
Arrays are used with respect to performance. Collections are not recommended to use with respect to performance.
Arrays can store only homogeneous (same type) of data. Collections can hold both homogeneous and heterogeneous elements.
Arrays do not have a single API. Collections having big list of methods.
Arrays can work with primitives and object types. Collections can hold only objects but not with primitive. If you pass as primitive internally convert to object.
See Also: Array & Arrays Class Examples See Also: Collection Framework and Examples

Java: ArrayList Vs Vector Class

java.util.ArrayList and java.util.Vector both implements List interface and maintains insertion order. It’s having many differences as below:

ArrayList vs Vector

ArrayList Vector
ArrayList is not synchronized. Vector is synchronized.
ArrayList increases 50% of the current array size if the number of elements exceeds its capacity. Vector increase 100% means doubles the array size when the total number of elements exceeds its capacity.
ArrayList is not a legacy class. It is introduced in JDK 1.2. Vector is a legacy class.
ArrayList is fast because it is non-synchronized. Vector is slow because it is synchronized, i.e., in a multithreading environment, it holds the other threads in the runnable or non-runnable state until the current thread releases the lock of the object.
ArrayList uses the Iterator interface to traverse the elements. A Vector can use the Iterator interface or Enumeration interface to traverse the elements.
See Also:ArrayList Class See Also:Java: Vector Class

ArrayList Example: traversing by the iterator

import java.util.*;
class ArrayListExample{
 public static void main(String args[]){    

  //creating arraylist of String
  List al=new ArrayList();
 //adding objecta in arraylist
  //traverse elements using Iterator
  Iterator itr=al.iterator();



Vector Example: Traversing by Enumerator

import java.util.*;
class VectorExample{
 public static void main(String args[]){
  Vector v=new Vector();//creating vector
  v.add("Umrao");//method of Collection
  v.addElement("Isha");//method of Vector
  //traverse elements using Enumeration
  Enumeration e=v.elements();



Java: String Vs StringBuffer Vs StringBuilder

String in Java

A String class represents an array of characters.

String Instance Creation
String instance can be created in two ways:

  • By assigning as Literals
    String title = "Facing Issues On IT";
  • By using the new keyword
    String title = new ("Facing Issues On IT");

Points to Remember for Java String

  • The string class is immutable in Java, so it’s easy to share it across different threads or functions.
  • When you create a String using double quotes, it first looks for the String with the same value in the JVM string pool, if match found it returns the reference else it creates the String object and then places it in the JVM String pool. This way JVM saves a lot of space by using the same String in different threads. But if a new operator is used, it will always explicitly creates a new String in the heap memory.
  • + operator overloading is used to concatenating two strings. Although internally it uses StringBuffer to perform this action.
  • String overrides equals() and hashCode() methods, two Strings are equal only if they have the same characters in the same order. Note that equals() method is case sensitive, so if you are not looking for case sensitive checks, you should use equalsIgnoreCase() method.
  • String value represents a string in the UTF-16 format.
  • String is a final/immutable class with all the fields as final except “private int hash”. This field contains the hashCode() function value and created only when the hashCode() method is called and then cached in this field. Furthermore, the hash is generated using the final fields of String class with some calculations, so every time hashCode() method is called, it will result in the same output. For the caller, it’s like calculations are happening every time but internally it’s cached in the hash field.

Why StringBuffer & StringBuilder?

The string class is immutable in java i.e whenever we do any manipulation in String like concatenation, substring, reverse, etc. always generate a new string and discard older String for garbage collection.

That’s the reason only Java introduced StringBuffer in JDK 1.4 and StringBuilder in JDK 1.5.

StringBuffer and StringBuilder are mutable objects and provide append(), insert(), delete() and substring() methods for String manipulation.

StringBuffer vs StringBuilder

Apart from similarities, Java StringBuffer and StringBuilder having differences:

  • StringBuffer is thread-safe because all of its methods are synchronized but the main disadvantage is performance.

Note: If you are working on a single-threaded environment go with StringBuilder and in a multithreaded environment use StringBuffer. In general scenarios for string manipulation, StringBuilder is better suited than StringBuffer because String buffer is synchronized.

String vs StringBuffer vs StringBuilder

String StringBuffer StringBuilder
Immutable Mutable Mutable
Legacy JDK 1.4 JDK 1.5
Thread Safe Thread Safe No Thread Safe
Synchronized Synchronized Not Synchronized
Performance slow in manipulation Performance slow in manipulation Performance faster in manipulation
String Concat (+) uses StringBuffer and StringBuilder internally NA NA
See Also: String Class Examples See Also: StringBuffer Examples See Also: StringBuilder Examples

Java: Abstract Class Vs Interface

Abstract class and interface in java used to provide abstraction but there are lots of differences:

Abstract Class Interface
Abstraction(0 to 100%) Abstraction(100%)
Abstract class implemented by keyword ‘extends Interface implemented by using keyword ‘implements
Abstract class also can not be instantiated but can be invoked if the main() method exists. Interface is completely abstract i.e can not create an instance of it.
Abstract class can have abstract and non-abstract methods. Interface methods are implicitly abstract and can not have an implementation(nobody)
Abstract class allowed final, non-final and static variables also. Interface allowed only final and static variables
Abstract class members are private, protected, etc. Interface members are public by default.
Abstract class can extend only one class but implements multiple java interfaces. Interface can extend other interfaces only.
Abstract class is fast compare to interface Interface is slow because it required extra indirection.
See Also: Java Abstract Class Examples See Also: Java Interface Examples

See Also:

Java: Method Overloading Vs Method Overriding


Method Overloading Method Overriding
Method Overloading is about the same function have different signatures. Method Overriding is about the same function, same signature but different classes connected through inheritance.
Method Overloading is a concept of compile-time polymorphism Method Overriding is a concept of run time polymorphism.
Method Overloading Example:

public class Employee
	public void print()
	//some code here
	public void print(String name)
	//some code here
	public void print(Employee employee)
	//some code here

Method Overriding Example:

public class Person
public void print(String name)
	//some code here
public class Employee extends Person
	public void print(String name)
	//some code here

See Also: Java Method Overloading in Detail See Also: Java Method Overriding in Detail

See Also:

Java: Difference between HashMap and Hashtable

HashMap and Hashtable both implements Map interface and used to store data in key and value pairs. Both use hashing techniques to get unique keys.

Apart from some similarities, there are many differences between HashMap and Hashtable classes as follows:

java.util.HashMap java.util.HashTable
HashMap class introduced in JDK 1.2. Hashtable is a legacy class.
HashMap inherits AbstractMap class. Hashtable inherits Dictionary class.
HashMap is traversed by Iterator. Hashtable is traversed by the Enumerator and Iterator.
Hashmap, Iterator is fail-fast. Hashtable, Enumerator is not fail-fast.
HashMap is not synchronized and not-thread safe. Hashtable is synchronized and thread safe.
HashMap can be synchronized by calling this code
Map m = Collections.synchronizedMap(hashMap);
Hashtable is internally synchronized and can’t be unsynchronized.
HashMap class allows only one null key and multiple null values. Hashtable doesn’t allow any null key or value.
HashMap is fast. Hashtable is slow.

For more detail:


JDBC : Difference between executeQuery() Vs executeUpdate() Vs execute() method

executeQuery(), executeUpdate() and execute() are the methods of java.sql.Statement interface of JDBC API which are used to execute the SQL statements.

executeQuery() Vs executeUpdate() Vs execute()

executeQuery() executeUpdate() execute()
This method is use to execute the SQL statements which retrieve some data from database. This statement is used to execute SQL statements which update or modify database. This method can be use for any kind of SQL statements.
This method returns a ResultSet object which contains the result returned by query. This method returns an int value which represent number of rows affected by the query. This will be 0 for statement which are returning nothing. This method return a Boolean value. TRUE indicates that query returned a ResultSet object and FALSE indicate returned an int value or returned nothing.
This method is use to execute select query. This method is use to execute non select query. This method is use to execute select and non select queries.
Any Type of SQL statements.

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Difference between Stored Procedure and functions

The differences between Stored procedures and Functions are given below:

See also :

Stored Procedure Function
Is used to perform business logic. Is used to perform calculation.
Must not have return type. Must have the return type.
May return zero or more values. May return only one values.
We can call function from procedure. Procedure can not be call from function.
Procedure supports input and output parameters Function supports only input parameters.
Exception handling using try/catch block can be used in stored procedures. Exception handling using try/catch can’t be used in user defined functions.

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JDBC: Difference between Statement, PreparedStatement and CallableSatement

JDBC API introduced statement, PreparedStatement and CallableStatemnet to execute different types of queries:

  1. Statement : Used to execute Normal SQL Queries.
  2. PreparedStatement: Used to execute dynamic or parameterized queries.
  3. CallableStatement: Used to execute StoredProcedure.

Statement Vs PreparedStatement Vs CallableStatement

Statement Prepared Statement Callable Statement
It is used to execute normal SQL queries. It is used to execute dynamic or parameterized SQL queries. It is used to execute Stored procedure or function.
It is proffered when particular query to be executed only once. It is proffered when particular query to be executed multiple times. It is proffered when stored procedure or functions to be executed.
You can no pass parameter to query by using this interface. You can pass parameter to query at run time by using this interface. You can pass three types of parameters by using this interface IN, OUT and IN OUT
This interface mainly used for DDL statements like CREATE, ALTER , DROP etc. This is used to be any kind of SQL queries which are used multiple times It is used with Stored Procedure and functions.
The performance of this interface is very low. The performance of this interface is better than query while using with multiple queries. Performance of this interface is very high because stored procedure execute on database end.
For More: Statement For More: Prepared Statement For More: Callable Interface

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