Java for Testing
Java for test automation: basics, OOP, keywords, strings, collections, exceptions and programs.
Java File I/O: Writing Files, Byte and Character Streams, and NIO.2
Java file I/O explained: writing files, InputStream/OutputStream and Reader/Writer hierarchies, buffering, java.nio Files and Path.
Java Certifications Guide (2026): Oracle Java SE 17 and 21, Plus Certifications for SDETs
Which Java certification to take: Oracle Java SE 21 and 17 Developer (OCP), Java Foundations, and certifications useful for SDETs.
Java HttpClient (Java 11+): GET, POST, Headers, Async Requests and Sockets
Java 11+ HttpClient with examples: GET and POST requests, headers, timeouts, async calls, reading JSON, and basic sockets.
Java Object Class Methods: equals, hashCode, toString, getClass, clone, wait and notify
The methods every Java class inherits from Object: equals and hashCode (and their contract), toString, getClass, clone, finalize, wait, notify and notifyAll.
OOPs Concepts in Java: Encapsulation, Inheritance, Polymorphism and Abstraction
The four OOPs concepts in Java explained with code: encapsulation, inheritance, polymorphism (overloading vs overriding) and abstraction.
What Is Java? History, Key Features and Why Testers Use It
What Java is and how it works: history from Sun to Oracle, bytecode and the JVM, the key features of Java explained, where it is used, and why testers learn it.
Java Operators and Expressions: Types, Precedence and Common Traps
Java operators with examples: arithmetic, relational, logical, assignment, ternary and instanceof, the precedence table, and traps like == and integer division.
Control Flow Statements in Java: if, switch, Loops, break and continue
Java control flow statements with examples: if-else, switch and switch expressions, for, for-each, while, do-while, break, continue and labeled loops.
Classes and Objects in Java: Fields, Constructors, Methods and Records
Classes and objects in Java explained: fields, methods, constructors, references, static vs instance, this, a page object example, and records for test data.
Exception Handling in Java: try-catch-finally, Checked vs Unchecked, Stack Traces
Exception handling in Java: hierarchy, try-catch-finally, try-with-resources, checked vs unchecked, throw vs throws, stack traces and custom exceptions.
Assertions in Java: the assert Keyword vs TestNG, JUnit and AssertJ
Java assertions: the assert keyword, enabling it with -ea, when not to use it, and how it differs from TestNG, JUnit and AssertJ assertions, hard and soft.
JAR Files in Java: Create, Run and Build Executable JARs (with Maven)
What JAR files are and how to use them: create with the jar tool, the manifest and Main-Class, java -jar vs -cp, fat JARs with Maven, and JARs testers run.
How to Read a File in Java: Scanner, Files and BufferedReader
Read files in Java with Scanner, Files.readString, readAllLines, Files.lines and BufferedReader, load CSV test data for TestNG, and fix path and encoding bugs.
Java SE vs Java EE (Jakarta EE) vs Java ME: Differences Explained
Java SE vs Java EE (now Jakarta EE) vs Java ME: what each edition contains, the javax to jakarta change, which one testers need, and a quick comparison table.
Java Keywords: Complete List of All 51 Reserved Keywords (with Examples)
Complete list of Java keywords: all 51 reserved keywords with meanings, contextual keywords like var and record, examples, common mistakes and FAQs.
Hello World in Java: Your First Program and the Structure of a Java Program
Write and run your first Java Hello World program, understand every part of a Java program's structure, and fix the 4 errors beginners hit most.
Primitive Data Types in Java: Sizes, Ranges, Defaults and Common Traps
All 8 primitive data types in Java with size, range and default value, verified with real Java output, plus overflow, integer division and float traps.
Count Vowels and Consonants in Java | Step-by-Step Guide with Code Examples
Learn how to count vowels and consonants in Java strings. Includes multiple methods, code examples, and handles uppercase, lowercase, and special characters.
JDBC and Database Connectivity in Java: Steps & Examples
Learn JDBC in Java — what it is, what a JDBC driver does, and the standard steps to connect a Java application to a database, with a full code example.
Java Strings, Encoding (UTF-8), Wrapper Classes and Exception Handling
Java strings and immutability, string encoding and charsets (UTF-8 vs ISO-8859-1), StringBuilder, wrapper classes and exception handling — with examples.