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.

Board Infinity
Skills you'll gain: Data Structures, Spring Boot, Restful API, Model View Controller, Spring Framework, Web Services, Java Programming, Java, Back-End Web Development, Authentications, Programming Principles, Authorization (Computing), Software Architecture, Algorithms, Object Oriented Programming (OOP)
Advanced · Course · 1 - 4 Weeks

EDUCBA
Skills you'll gain: Microservices, Spring Framework, Spring Boot, YAML, MongoDB, Application Deployment, NoSQL, Ajax, Software Architecture, Java, Development Environment, Scalability, Load Balancing, Data Integration, Restful API, Configuration Management, Application Performance Management, Continuous Deployment, Web Applications, Javascript and jQuery
Mixed · Course · 1 - 3 Months

Amazon
Skills you'll gain: Object Oriented Programming (OOP), Object Oriented Design, Java, File Management, Data Import/Export, Maintainability, Debugging, Software Development
Beginner · Course · 1 - 4 Weeks

Skills you'll gain: Java Programming, Java, Integrated Development Environments, Mobile Development, Computer Programming, Object Oriented Programming (OOP), Debugging, Data Structures
Beginner · Guided Project · Less Than 2 Hours

Skills you'll gain: Identity and Access Management, Cloud Infrastructure, Google Cloud Platform, Cloud Computing, Cloud Services, Cloud Computing Architecture, Cloud Storage, Data Storage Technologies, Key Management, Security Controls, System Monitoring
Intermediate · Course · 1 - 3 Months

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, Program Development, Programming Principles, Computational Logic, Software Development, Software Development Life Cycle, Debugging
Build toward a degree
Beginner · Course · 1 - 4 Weeks

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

Skills you'll gain: Object Oriented Design, Programming Principles, Data Import/Export, Integrated Development Environments, Debugging, File Management
Beginner · Course · 3 - 6 Months

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: Object-Relational Mapping, Spring Framework, Hibernate (Java), Apache Maven, Model View Controller, Relational Databases, Database Design, MySQL, Web Applications, Java Platform Enterprise Edition (J2EE), Java Programming, Java, Full-Stack Web Development, Database Application, Database Development, Authentications, Object Oriented Design, Back-End Web Development, Object Oriented Programming (OOP), Software Design Patterns
Beginner · Specialization · 1 - 3 Months

Skills you'll gain: Spring Framework, Java, Object Oriented Design, Object Oriented Programming (OOP), Software Design Patterns, Model View Controller, Middleware, Extensible Markup Language (XML), Integration Testing, Dependency Analysis
Mixed · Course · 1 - 4 Weeks