The Build command performs an incremental build that compiles all resources modified since the last build. To trigger an incremental build, either:
You can also incrementally build single projects. Select the project that you want to build and:
To rebuild all workbench resources that have an associated builder (e.g. Java projects), select Project > Rebuild All from the menu bar.
To rebuild all resources contained in a project, select the project and select Project > Rebuild Project from the menu bar.
Building a Java program
Building automatically
Working with build paths
Adding a JAR file to the build path
Adding a library folder to the build path
Viewing and editing a project's build path