Bug 56965 Classpath variable name has to be a valid Java identifier
I20040330 window>preferences>java>classpath variables>new type '444' an error is displayed in the dialog : Invalid name: ''444' is not a valid Java identifier.'. I don't see any reason why the name of the variable has to be a valid Java identifier.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/VariableCreationDialog.java
dialog.setText(NewWizardMessages.getString("VariableCreationDialog.extjardialog.text")); 
		dialog.setFilterExtensions(new String[] {"*.jar;*.zip"}); 
		dialog.setFilterPath(initPath);
		String res= dialog.open();
		if (res != null) {
			fDialogSettings.put(IUIConstants.DIALOGSTORE_LASTEXTJAR, dialog.getFilterPath());
			return new Path(res).makeAbsolute();
		}
		return null;
	}
	
	private IPath chooseExtDirectory() {
		String initPath= getInitPath();
		
		DirectoryDialog dialog= new DirectoryDialog(getShell());
		dialog.setText(NewWizardMessages.getString("VariableCreationDialog.extdirdialog.text")); 
		dialog.setMessage(NewWizardMessages.getString("VariableCreationDialog.extdirdialog.message")); 
		dialog.setFilterPath(initPath);
		String res= dialog.open();
		if (res != null) {
			fDialogSettings.put(IUIConstants.DIALOGSTORE_LASTEXTJAR, dialog.getFilterPath());
			return new Path(res);
		}
		return null;		
	}
	
		
	
}