Core Java courses can help you learn object-oriented programming, exception handling, multithreading, and Java Collections. You can build skills in writing efficient algorithms, debugging code, and developing user interfaces. Many courses introduce tools like Eclipse and IntelliJ IDEA, which are commonly used for coding and testing Java applications, along with frameworks such as Spring and Hibernate that facilitate web development and database management.
Codio
Skills you'll gain: Apache Maven, JSON, JUnit, Java Programming, Java, Restful API, Integrated Development Environments, Programming Principles, Data Structures, Object Oriented Programming (OOP), Network Protocols, Unit Testing, Style Guides
Intermediate · Course · 1 - 4 Weeks

Board Infinity
Skills you'll gain: Data Structures, Spring Boot, Restful API, Model View Controller, Spring Framework, Java Programming, Java, Authentications, Authorization (Computing), Microservices, Algorithms, Object Oriented Programming (OOP), Dependency Analysis
Advanced · Course · 1 - 4 Weeks

Oracle
Skills you'll gain: Java, Object Oriented Programming (OOP), Oracle Cloud, Computer Programming, Cloud Development, Integrated Development Environments, Development Environment
Beginner · Course · 1 - 4 Weeks

Heriot-Watt University
Skills you'll gain: Object Oriented Programming (OOP), Java, Java Programming, Computer Programming, Application Development, Programming Principles, Computational Logic, Software Development, Debugging, Data Structures
Build toward a degree
Beginner · Course · 1 - 4 Weeks

EDUCBA
Skills you'll gain: Microservices, Spring Framework, Spring Boot, YAML, MongoDB, Application Deployment, NoSQL, Ajax, Software Architecture, Java, Scalability, Load Balancing, Restful API, Web Applications, File Management
Mixed · Course · 1 - 3 Months

Skills you'll gain: Identity and Access Management, Cloud Infrastructure, Google Cloud Platform, Infrastructure As A Service (IaaS), Cloud Computing, Cloud Management, Cloud Storage, Data Storage Technologies, NoSQL, System Monitoring, Encryption
Intermediate · Course · 1 - 3 Months

Skills you'll gain: JUnit, Restful API, Software Design, JSON, Software Testing
Intermediate · Course · 3 - 6 Months

LearnQuest
Skills you'll gain: Apache Maven, Spring Framework, Microservices, Java Platform Enterprise Edition (J2EE), Spring Boot, Java, Java Programming, Back-End Web Development, Software Architecture, Load Balancing, Application Servers, Restful API, Web Applications, Scalability
Advanced · Course · 1 - 4 Weeks

Skills you'll gain: Java Programming, Java, Object Oriented Programming (OOP), Oracle SQL Developer, Oracle Databases
Intermediate · Specialization · 1 - 3 Months

Skills you'll gain: Load Balancing, ASP.NET, Test Driven Development (TDD), Debugging, C# (Programming Language), Software Testing, Scalability, Performance Testing, Restful API, Unit Testing, Web Development, Microservices, .NET Framework, Object-Relational Mapping, Software Architecture, API Testing, Web Applications, Test Case, Distributed Computing, Redis
Intermediate · Specialization · 3 - 6 Months

Skills you'll gain: Java Programming, Java, Development Environment, Computer Programming, Integrated Development Environments, Object Oriented Programming (OOP), Data Structures, File I/O, Debugging
Beginner · Course · 1 - 3 Months

LearnKartS
Skills you'll gain: JUnit, File I/O, Unit Testing, Program Development, Debugging, Java, Maintainability, Software Development, Secure Coding, Software Testing, Test Case, Authentications, Application Security, Cryptography, Object Oriented Programming (OOP), Eclipse (Software), Integrated Development Environments, Encryption, Data Structures
Beginner · Course · 1 - 4 Weeks