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: Microservices, Spring Framework, Spring Boot, YAML, MongoDB, Application Deployment, NoSQL, Ajax, Software Architecture, Java Programming, Frontend Integration, Java, Development Environment, Scalability, Load Balancing, Data Integration, Configuration Management, File I/O, File Management
★ 4.8 (22) · Mixed · Course · 1 - 3 Months

Rice University
Skills you'll gain: Java Programming, Java, Data Structures, Programming Principles, Algorithms
★ 4.5 (664) · Intermediate · Course · 1 - 3 Months

Skills you'll gain: Selenium (Software), Java, Java Programming, File I/O, File Management, Cascading Style Sheets (CSS), Extensible Markup Language (XML), Test Automation, Extensible Languages and XML, Test Script Development, Web Scraping, Apache, Web Development Tools, Data Import/Export, Verification And Validation, HTML and CSS, Hypertext Markup Language (HTML)
Intermediate · Course · 1 - 3 Months

Codio
Skills you'll gain: Algorithms, Data Structures, Java, Java Programming, Other Programming Languages
★ 3.4 (9) · Intermediate · Course · 1 - 4 Weeks

Skills you'll gain: Java Programming, Java, Integrated Development Environments, Mobile Development, Computer Programming, Programming Principles, Data Structures
★ 4.4 (180) · Beginner · Guided Project · Less Than 2 Hours

LearnQuest
Skills you'll gain: Spring Framework, Java Programming, Java, File I/O, Java Platform Enterprise Edition (J2EE), Object Oriented Programming (OOP), Application Frameworks, Code Reusability, Data Structures, File Management
★ 4.7 (222) · Intermediate · Course · 1 - 3 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: Spring Framework, Java Programming, Java, Application Frameworks, Object Oriented Design, Object Oriented Programming (OOP), Software Design Patterns, Extensible Markup Language (XML)
★ 4.7 (13) · Mixed · Course · 1 - 4 Weeks

Board Infinity
Skills you'll gain: Classification Algorithms, Java Programming, Data Preprocessing, Machine Learning Software, Model Training, Model Deployment, Model Evaluation, Decision Tree Learning, Logistic Regression
Beginner · Course · 1 - 4 Weeks

LearnQuest
Skills you'll gain: Spring Framework, JUnit, Application Frameworks, Unit Testing, Java Programming, Enterprise Application Management, Integration Testing, Configuration Management, Development Environment, Extensible Markup Language (XML), Context Management
★ 3.8 (455) · Intermediate · Course · 1 - 4 Weeks

Skills you'll gain: Distributed Computing, Java Programming, Load Balancing, Middleware, Database Management Systems, NoSQL, Event-Driven Programming, Databases, Systems Architecture, Software Architecture, Computer Systems, Remote Access Systems, Microservices, Scalability, Service Management, Communication Systems
Intermediate · Course · 1 - 3 Months

Skills you'll gain: IntelliJ IDEA, Integrated Development Environments, Java Programming, Java, Development Environment, Debugging, Object Oriented Programming (OOP), Programming Principles
Beginner · Course · 1 - 4 Weeks