Java Cross Engineering call class or method in Eclipse

In the Eclipse Authoring Java program, sometimes we need to invoke another project's class or method, as follows there are two Java project

When project a wants to invoke MOTHOD1 in Project B, first make these two items open

Then right-click on Project A; Enter build path (build route)-->configure build paths (configuration build path)-->java build paths (Java build path) Select Projects (Project)

Click Add on the right

Then you'll see that the project is open, and the app is selected.

Java Cross Engineering call class or method in Eclipse