Bug 13034 Cannot create a Source Folder in a new Java Project
build 20020404 If you try and create a Source Folder in a Java Project you have just created you get an error preventing you from hitting finish. STEPS 1) Create Java Project Foo 2) Open New->Source Folder 3) Enter Bar as the name - you will get "Cannot nest entry Bar inside entry Foo/Bar" 4) Create a folder Bar. 5) Add it as a source folder in the Properties Dialog for Foo. No problem.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/NewSourceFolderWizardPage.java
public NewSourceFolderWizardPage() {
		super(PAGE_NAME);
		
		setTitle(NewWizardMessages.getString("NewSourceFolderWizardPage.title")); 
		setDescription(NewWizardMessages.getString("NewSourceFolderWizardPage.description"));		 
		
		fWorkspaceRoot= ResourcesPlugin.getWorkspace().getRoot();
		
		RootFieldAdapter adapter= new RootFieldAdapter();
		
		fProjectField= new StringButtonDialogField(adapter);
		fProjectField.setDialogFieldListener(adapter);
		fProjectField.setLabelText(NewWizardMessages.getString("NewSourceFolderWizardPage.project.label")); 
		fProjectField.setButtonLabel(NewWizardMessages.getString("NewSourceFolderWizardPage.project.button"));	 
		
		fRootDialogField= new StringButtonDialogField(adapter);
		fRootDialogField.setDialogFieldListener(adapter);
		fRootDialogField.setLabelText(NewWizardMessages.getString("NewSourceFolderWizardPage.root.label")); 
		fRootDialogField.setButtonLabel(NewWizardMessages.getString("NewSourceFolderWizardPage.root.button")); 
		
		fEditClassPathField= new SelectionButtonDialogField(SWT.PUSH);
		fEditClassPathField.setDialogFieldListener(adapter);
		fEditClassPathField.setLabelText(NewWizardMessages.getString("NewSourceFolderWizardPage.editclasspath.button"));		 
		
		fRootStatus= new StatusInfo();
		fProjectStatus= new StatusInfo();
	}