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

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

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

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: JUnit, Restful API, Software Design, JSON, Software Testing
Intermediate · Course · 3 - 6 Months

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

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: 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: Apache Maven, Java, Java Platform Enterprise Edition (J2EE), Object Oriented Design, Hibernate (Java), Unit Testing, File I/O, Docker (Software), Software Design Patterns, Integrated Development Environments, Object-Relational Mapping, Functional Design, Maintainability, System Configuration
Beginner · Specialization · 3 - 6 Months

Skills you'll gain: JUnit, Apache Maven, Spring Boot, Model View Controller, Unit Testing, Microservices, Application Development, Spring Framework, Redis, Restful API, YAML, Java, Java Programming, MongoDB, Application Deployment, NoSQL, Ajax, Hibernate (Java), Data Persistence, Software Testing
Beginner · Specialization · 3 - 6 Months

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

Pearson
Skills you'll gain: Java, Transaction Processing, File I/O, Java Programming, Data Access, Object Oriented Design, Data Persistence, Stored Procedure, SQL, Integration Testing, Application Development, Command-Line Interface, Application Deployment, Data Integrity, Databases, Programming Principles, Application Programming Interface (API), Secure Coding, System Programming, Mitigation
Intermediate · Specialization · 1 - 3 Months