This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
"Ljava/lang/String;", including the "L" and the ";", is the way Java class names are indicated in the Java class file format. There's a whole system of codes to name different types: I for int, Z for boolean, and Lclass/name; for classes.
Without seeing exactly what ReflectionUtil.invokeGetter is doing, it's hard to say what's causing this error.