To enable automatic building:
Enable Project > Build Automatically orTo disable automatic building:
select the Window > Preferences > General > Workspace > Build automatically checkbox.
Disable Project > Build Automatically or
clear the Window > Preferences > General > Workspace > Build automatically checkbox.
Building a Java program
Building manually
Viewing compilation errors and warnings
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