The type org.eclipse.core.runtime.IProgressMonitor cannot be resolved

 CompilationUnit unit = (CompilationUnit) parser.createAST(null);

ERROR:The type org.eclipse.core.runtime.IProgressMonitor cannot be resolved. It is indirectly referenced from required .class files.

一开始尝试直接下org.eclipse.core.runtime，但看了好几个version，都没有IProgressMonitor.class，最后是在这个链接里的jar包找到的。