What David pointed out explains why the following code won't compile:
The error message you get may seem a bit cryptic, but it means that the constructor in "Level03" is illegal since Java will try and insert an implicit call to "super()". But "Level02" doesn't supply a default constructor, and Java won't add one because there is another constructor already defined.
So the [implicit] call to "super()" in the "Level03" constructor fails, and this code won't compile. This may be too advanced for a "Beginning Java"
thread, but understanding constructors is a key aspect of learning Java.