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.

EDUCBA
Skills you'll gain: File I/O, Object Oriented Programming (OOP), Java Programming, Data Structures, Java, Data Persistence, Programming Principles, Data Store
Intermediate · Course · 1 - 4 Weeks

Skills you'll gain: Selenium (Software), Ajax, Java Programming, Test Script Development, Java, Software Testing, Test Automation, Scripting, Automation, Cascading Style Sheets (CSS)
Intermediate · Course · 3 - 6 Months

Vanderbilt University
Skills you'll gain: Android Studio, Android Development, Object Oriented Programming (OOP), Android (Operating System), Java Programming, Java, Mobile Development, Object Oriented Design, Data Structures, Integrated Development Environments, Programming Principles, Computer Programming, Development Environment
Beginner · Course · 1 - 3 Months
Skills you'll gain: Java, Java Programming, Performance Tuning, Data Structures, Software Engineering, Tree Maps, Scalability, Algorithms, Benchmarking, Theoretical Computer Science
Advanced · Course · 1 - 4 Weeks

Skills you'll gain: Java Platform Enterprise Edition (J2EE), Java Programming, Object-Relational Mapping, Java, Application Servers, Middleware, Application Deployment, Data Persistence, Event-Driven Programming, Enterprise Application Management, Server Side, Code Reusability, Context Management, Transaction Processing, Business Logic, Query Languages
Intermediate · Course · 1 - 4 Weeks

Skills you'll gain: Web Services, Restful API, Apache Maven, Build Tools, Spring Boot, Spring Framework, Gradle, Simple Object Access Protocol (SOAP), Application Programming Interface (API), Java, Java Programming, API Design, Object-Relational Mapping, Data Persistence, JSON, Extensible Markup Language (XML)
Intermediate · Course · 3 - 6 Months

Peking University
Skills you'll gain: Java Programming, Java, Object Oriented Programming (OOP), Program Development, Object Oriented Design, Data Structures, Computer Programming, Programming Principles, C++ (Programming Language), Maintainability, JUnit, C and C++, UI Components, User Interface (UI), Software Design, Application Programming Interface (API), Event-Driven Programming, Data Access, File I/O
Intermediate · Course · 1 - 3 Months

LearnQuest
Skills you'll gain: Java Programming, Java, Object Oriented Programming (OOP), Computer Programming, Object Oriented Design, Development Environment, Programming Principles, Data Structures
Intermediate · Course · 1 - 4 Weeks

Skills you'll gain: Object Oriented Design, Computer Programming, Code Reusability, Memory Management
Intermediate · Course · 1 - 4 Weeks

Skills you'll gain: Spring Framework, JUnit, Restful API, Spring Boot, Unit Testing, Java Programming, Java, Hibernate (Java), Model View Controller, Java Platform Enterprise Edition (J2EE), Web Services, Object-Relational Mapping, Software Testing, Test Script Development, Apache Maven, Data Access, Databases, Database Management, Web Applications, Gradle
Beginner · Course · 3 - 6 Months

Board Infinity
Skills you'll gain: Java Platform Enterprise Edition (J2EE), Application Performance Management, Software Design Patterns, Java, Enterprise Architecture, Java Programming, Enterprise Application Management, Secure Coding, Software Design, Model View Controller, System Monitoring, Security Controls, Software Architecture, Application Security, Maintainability, Application Frameworks, Programming Principles, Authorization (Computing), Authentications, Program Development
Intermediate · Course · 1 - 4 Weeks

Skills you'll gain: Maintainability, Computational Logic
Intermediate · Course · 1 - 4 Weeks