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
fPathStatus= new StatusInfo();
		
		NewVariableAdapter adapter= new NewVariableAdapter();
		fNameField= new StringDialogField();
		fNameField.setDialogFieldListener(adapter);
		fNameField.setLabelText(NewWizardMessages.getString("VariableCreationDialog.name.label")); 
		fPathField= new StringButtonDialogField(adapter);
		fPathField.setDialogFieldListener(adapter);
		fPathField.setLabelText(NewWizardMessages.getString("VariableCreationDialog.path.label")); 
		fPathField.setButtonLabel(NewWizardMessages.getString("VariableCreationDialog.path.file.button")); 
		
		fDirButton= new SelectionButtonDialogField(SWT.PUSH);
		fDirButton.setDialogFieldListener(adapter);
		fDirButton.setLabelText(NewWizardMessages.getString("VariableCreationDialog.path.dir.button")); 
		
		fExistingNames= existingNames;
		
		if (element != null) {
			fNameField.setText(element.getName());
			fPathField.setText(element.getPath().toString());
			fExistingNames.remove(element.getName());
		} else {
			fNameField.setText(""); 
			fPathField.setText(""); 
		}
	}
	
	/*
	 * @see Windows#configureShell
	 */