This is a common error when starting out with Java:
DefaultValues.java:5: error: variable example might not have been initialized
System.out.println(example);
In Java, Class instance properties are initialized to default values if not explicitly defined with an initial value. For local variables however (e.g. variables local within method or a block scope), default values are not automatically assigned, meaning that you must explicitly initialize them otherwise you’ll see the compile error above.
This is described in the Java tutorial here.