Bug 16858 Preceding space in package compression pattern sometimes ignored
(In the following discussion, all patterns were entered without the enclosing quote marks.) The pattern "1 " causes one character of each package name to be displayed with a single space separator between them. The pattern " 1 " causes one space to precede the first single-character package name and two spaces to appear between each one. Both of the above cases were expected. However, if you set the patttern to " 1" (i.e. space before, but no space after), no spaces are displayed in the result.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/viewsupport/JavaElementLabels.java
if (getFlag(flags, F_POST_QUALIFIED)) {
				buf.append(CONCAT_STRING);
				getTypeLabel(field.getDeclaringType(), T_FULLY_QUALIFIED, buf);
			}
			
		} catch (JavaModelException e) {
			JavaPlugin.log(e); 
		}			
	}
	/**
	 * Appends the label for a initializer to a StringBuffer. Considers the I_* flags.
	 */	
	public static void getInitializerLabel(IInitializer initializer, int flags, StringBuffer buf) {
		
		if (getFlag(flags, I_FULLY_QUALIFIED)) {
			getTypeLabel(initializer.getDeclaringType(), T_FULLY_QUALIFIED, buf);
			buf.append('.');
		}
		buf.append(JavaUIMessages.getString("JavaElementLabels.initializer")); 
		
		if (getFlag(flags, I_POST_QUALIFIED)) {
			buf.append(CONCAT_STRING);
			getTypeLabel(initializer.getDeclaringType(), T_FULLY_QUALIFIED, buf);
		}
	}
	/**
	 * Appends the label for a type to a StringBuffer. Considers the T_* flags.
	 */