Building automatically

To enable automatic building:

Enable Project > Build Automatically or
select the Window > Preferences > General > Workspace > Build automatically checkbox.
To disable automatic building:
Disable Project > Build Automatically or
clear the Window > Preferences > General > Workspace > Build automatically checkbox.

Related concepts

Java builder
Build class path

Related tasks

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

Related reference
Java Build path