Java Backend Development Essentials
Core JDBC Concepts and Usage
JDBC Query Methods: executeQuery() vs. executeUpdate()
The method executeQuery() is used when you want to retrieve data from the database, typically using a SELECT statement. It returns a ResultSet object which contains the data returned by the query.
Example:
ResultSet rs = statement.executeQuery("SELECT * FROM users");
while (rs.next()) {
System.out.println(rs.getString("username"));
}The method executeUpdate() is used for SQL statements that change the data in the
Mathematical Transforms for Signal Analysis
Fourier Series vs. Fourier Transform
Great question! Fourier Series and Fourier Transform are both mathematical tools used to analyze signals, but they serve different purposes.
- Fourier Series: This is used to represent a periodic function as a sum of sines and cosines. It decomposes a repeating signal into its frequency components. Essentially, if you have a function that repeats over time, the Fourier Series breaks it down into simpler waves.
- Fourier Transform: This, on the other hand, is used for
Practical Java Code Examples: JDBC, Threads, Servlets, Sockets
Java Programming Examples Collection
This document presents a collection of practical Java programming examples, covering database interactions with MySQL using JDBC, multithreading concepts, Swing UI development, and basic web application development with Servlets, along with a simple network client.
JDBC Database Operations
These examples demonstrate how to connect to a MySQL database and perform common operations like counting records, creating tables, and retrieving data.
Count Records in MySQL
Read MoreComputer Networking Fundamentals: Models, Protocols, Topologies
Computer Network Definition & OSI Model Openness
A computer network is a group of two or more interconnected computers that can communicate and share resources such as files, printers, applications, or internet access. The main goal of a network is to enable data sharing and communication between devices.
The OSI (Open Systems Interconnection) model is called “open” because it was developed as a universal, standardized framework that is not tied to any specific vendor, product, or technology.
Read MorePython Data Essentials: Pandas, NumPy, and String Methods
Introduction to Pandas
Pandas is a powerful and flexible Python library used for data manipulation, analysis, and cleaning. It is suitable for handling different kinds of data, such as:
- Tabular data with heterogeneous columns (different types of data in a single dataset).
- Ordered & unordered time-series data (data arranged based on time or random order).
- Arbitrary matrix data with row & column labels.
- Unlabeled data, making it useful for raw statistical data processing.
Essential Pandas Operations
Pandas
Read MoreEssential Networking Concepts and Technologies
Ethernet Frame Format
The Ethernet frame consists of the following fields:
- Preamble: (7 bytes) Synchronization pattern.
- Start Frame Delimiter (SFD): (1 byte) Marks the start of the frame.
- Destination Address: (6 bytes) MAC address of the recipient.
- Source Address: (6 bytes) MAC address of the sender.
- Protocol ID (TPID) / Length: (2 bytes) Indicates the type of protocol or the length of the data field.
- Tag Control Information (TCI): (4 bytes, for VLAN-tagged frames) Includes:
- Priority: (3 bits) User Priority