Issues:

• At least one fixed test per possible condition for a given grade would be good to have, so a fixed test fails before a random test. Especially for edges of ranges which determine a final grade.
• It's not necessary to have both random tests and complete domain tests. One of these will do.
• ComplexTest does not adhere to Java naming conventions.

Suggestions:

• "Testing with exam = " + 99 + " and projects = " + 1 - you don;t need concatenation if values are constant. Just a literal string will do.

Java translation