Build tools are software applications that automate the process of compiling source code into executable programs. They help developers manage dependencies, run tests, and package applications for deployment. Common build tools include Maven, Gradle, and Ant, which streamline the development workflow and ensure consistency across different environments. These tools often use configuration files to define the build process, allowing developers to specify tasks such as compiling code, running tests, and creating documentation. By automating these tasks, build tools save time and reduce the risk of human error, making it easier for teams to collaborate and deliver high-quality software.