Java Developer Roadmap for Freshers

From syntax to collections, OOP and a small Spring-style project: what a fresher Java developer is asked in interviews.

7 milestones · ~180 hours total

1. 1

   Syntax and basics

   ~25h

   Variables, types, operators, control flow, arrays and methods. Write 20 small programs.

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2. 2

   Object-oriented Java

   ~30h

   Classes, inheritance, interfaces, abstract classes, polymorphism and encapsulation, with a mini project.

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3. 3

   Collections and generics

   ~25h

   List, Set, Map, Queue, iterators, Comparable and Comparator, and when to use each.

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4. 4

   Exceptions, strings and I/O

   ~20h

   Checked and unchecked exceptions, try-with-resources, String immutability, files and streams.

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5. 5

   Multithreading and concurrency

   ~25h

   Threads, Runnable, synchronization, volatile, executors and ConcurrentHashMap.

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6. 6

   SQL, JDBC and a project

   ~40h

   Connect a Java program to a database, then build a small REST service. Put it on GitHub.

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7. 7

   Interview rounds

   ~15h

   Take the Java rated tests, then revise hash map internals, equals/hashCode and the JVM memory model.

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