The Java ecosystem refers to the collection of tools, libraries, frameworks, and technologies that support the development and deployment of applications using the Java programming language. It includes the Java Development Kit (JDK), which provides the necessary tools for writing and compiling Java code, as well as the Java Runtime Environment (JRE), which allows Java applications to run on various devices. Within the Java ecosystem, popular frameworks like Spring and Hibernate help developers build robust applications more efficiently. Additionally, the ecosystem is supported by a vast community and resources, including Maven for project management and JUnit for testing, making it easier for developers to create high-quality software.