Java Certification

Java certification syllabus & coverage

This certification tests genuine comprehension of Java language fundamentals, idiomatic patterns, data structures, and production practices. Questions are sampled across all course modules:

• Getting Started: Why Java still runs banks, Android and big-data systems, how to install JDK 21 on any OS, and your first Java program explained line by line.
• Fundamentals: Variables, the eight primitive types, operators, type casting, integer overflow and reading keyboard input with Scanner, with the compiler errors each one causes.
• Flow Control: if/else, the ternary operator, classic switch and Java 21 switch expressions, while, do-while and for loops, break, continue and labels.
• Strings & Arrays: Java Strings and arrays: immutability, == vs equals, StringBuilder, text blocks, formatting, Arrays helpers, 2-D arrays and the index errors they cause.
• Methods: Java methods: parameters and return values, pass-by-value traced step by step, overloading, varargs, static vs instance, recursion, scope and final.
• Classes & Objects: Java classes and objects: fields, constructors, this, encapsulation, static members, toString/equals/hashCode, records, immutability and null.
• Inheritance & Interfaces: Java inheritance and interfaces: extends, super, @Override, dynamic dispatch, abstract classes, default methods, sealed types and composition.
• Exceptions: Java exceptions explained: checked vs unchecked, try/catch/finally, try-with-resources, custom exceptions, cause chains and how to read a stack trace.
• Collections: List, Set and Map in Java: ArrayList, HashSet, TreeMap and friends, sorting with Comparable and Comparator, the equals/hashCode contract, and picking the right one.
• Generics, Lambdas & Streams: Java generics, wildcards and type erasure, then lambdas, functional interfaces, method references and the Stream API — and when a plain loop is better.
• Concurrency: Java threads without the fear: Runnable and join, race conditions, synchronized, atomics, ExecutorService, CompletableFuture, virtual threads and deadlock.
• Errors & Debugging: The 15 Java errors every beginner hits, with the real javac and JVM messages, how to read a stack trace, and the debugger, logging and jshell habits that fix bugs fast.
• Java + Tools: Nine mini-labs on Java as it is used at work: Maven, Gradle, JUnit 5, Spring Boot, PostgreSQL over JDBC, Hibernate, Docker, Kafka and Git.
• Data Structures & Algorithms: Stacks, queues, linked lists, trees, heaps and graphs built by hand in Java, then the java.util classes that replace them, plus searching, sorting and DP.
• Problem Solving: A repeatable way to crack coding problems in Java: read it, break it down, test small cases, then apply one of eight patterns that cover most interviews.
• Interview Questions: Sixty Java interview questions — 25 junior, 25 mid-level, 10 senior — with model answers, what each is really testing, a coding round and a take-home checklist.
• Job Ready: What a Java resume must show, three portfolio projects that get Java callbacks, where Java jobs are, and the certification exam that closes the handbook.

Exam rules & grading

The exam features 25 multiple-choice questions with a time limit of 35 minutes. A passing score of 70% or higher issues a permanent certificate with a verifiable credential ID that can be attached directly to your resume and LinkedIn Profile.

Frequently asked questions